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[cat] La leucèmia limfoblàstica aguda (LLA) és l’expansió clonal de cèl·lules malignes originades a partir de progenitors hematopoètics i és el càncer pediàtric més freqüent. La supervivència dels pacients pediàtrics afectes de LLA ha augmentat de forma important en les últimes dècades, actualment supera el 90% en països de renda alta. La intensitat terapèutica dels règims quimioteràpics actuals ha arribat al límit de la tolerància. D’aquesta manera, per a millorar el pronòstic és més important disminuir-ne la toxicitat, més que incrementar-ne la intensitat. L’asparaginasa (ASP) és un quimioteràpic essencial en el tractament de la LLA però s’associa a toxicitats freqüents i a vegades greus, com hipersensibilitat i pancreatitis, que poden tenir un impacte en la supervivència. En la pràctica clínica s’utilitzen 3 formulacions d’ASP, dues derivades d’E. coli (una nativa i una pegilada: E. coli-ASP nativa, PEG-ASP) i una d’Erwinia chrysanthemi (Erwinia-ASP), amb un patró similar de toxicitat excepte una potencial menor immunogenicitat de PEG-ASP respecte E. coli-ASP nativa. La hipersensibilitat és la toxicitat més freqüent i pot manifestar-se com al·lèrgia real (clínica d’al·lèrgia amb inactivació del fàrmac), pseudoal·lèrgia (clínica d’al·lèrgia sense inactivació del fàrmac) i inactivació silent (IS) (inactivació del fàrmac sense cap simptomatologia associada). S’han relacionat certs polimorfismes genètics amb la pancreatitis i la hipersensibilitat associades a ASP. Per a avaluar l’efectivitat de l’ASP, la tècnica gold stantard és la determinació d’activitat d’asparaginasa en sèrum (AAS). Un nivell ≥ 100 UI/L defineix una AAS en rang terapèutic. Partint d’aquest context, en aquest treball de tesi vam plantejar les següents hipòtesis: l’anàlisi de polimorfismes genètics relacionats amb toxicitat a ASP podria identificar els pacients amb major risc de pancreatitis o al·lèrgia; la incidència d'al·lèrgia en pacients pediàtrics que reben un esquema seqüencial d’ASP (E. coli nativa-ASP seguida de PEG-ASP) podria ser major a la dels que reben únicament PEG-ASP dins del mateix protocol i, finalment; que amb la dosi més baixa de PEG-ASP (1.000 UI/m2) es podrien aconseguir nivells d’AAS suficients per a una correcta efectivitat clínica. Per a donar resposta a aquestes hipòtesis, vam enfocar els següents objectius: estudiar la correlació entre els polimorfismes en el gen de l’asparagin-sintetasa (ASNS) relacionats amb toxicitat a ASP en una sèrie de pacients pediàtrics afectes de LLA i comparar la incidència d’al·lèrgia clínica en pacients pediàtrics amb LLA que han rebut diferents esquemes d'administració d’ASP dins el mateix protocol terapèutic. En la nostra població d’estudi, els polimorfismes rs3757676 i rs3832526, descrits prèviament com a haplotip de risc i protector del gen ASNS enfront al·lèrgia i pancreatitis, no van tenir una relació clara amb l’aparició d’aquestes toxicitats. El risc de presentar al·lèrgia a ASP es va associar tant amb el fet de rebre un protocol d’alt risc de recaiguda com el fet de pertànyer a l’ètnia llatinoamericana. El risc de presentar pancreatitis secundària a ASP es va associar amb el fet de tenir una edat ≥ 10 anys en el moment del diagnòstic. En el nostre protocol de tractament LAL/SEHOP-PETHEMA 2013, l’ús de PEG-ASP en primera línia es va associar amb una menor incidència d'al·lèrgia clínica que l'observada en l’ús seqüencial d’E. coli-ASP nativa seguida de PEG-ASP. PEG-ASP a una dosi de 1.000 UI/m2 intramuscular va ser eficaç per assolir una AAS suficient en més del 90% dels pacients. La incidència d'inactivació silent en els pacients tractats amb PEG-ASP en primera línia va ser molt baixa. Vam detectar una associació significativa entre els nivells d’AAS i l’increment dels nivells d’amoni sèric, la disminució dels nivells d’albúmina, i l’increment dels nivells de triglicèrids. No es van observar diferències significatives en la incidència de pancreatitis en funció de la formulació d’ASP utilitzada., [eng] Acute lymphoblastic leukaemia (ALL) is the clonal expansion of malignant cells originating from haematopoietic progenitors and is the most common paediatric cancer. Survival of paediatric ALL patients has increased significantly in recent decades, now exceeding 90% in high-income countries. The therapeutic intensity of current chemotherapy regimens has reached the limit of tolerance. Thus, to improve prognosis, it is more important to decrease toxicity than to increase intensity. Asparaginase (ASP) is an essential chemotherapy drug in the treatment of ALL but is associated with frequent and sometimes severe toxicities, such as hypersensitivity and pancreatitis, which can impact survival. In clinical practice, 3 ASP formulations are used, two derived from E. coli (one native and one pegylated: native E. coli-ASP, PEG-ASP) and one from Erwinia chrysanthemi (Erwinia-ASP), with a similar pattern of toxicity except for a potential lower immunogenicity of PEG-ASP compared to native E. coli-ASP. Hypersensitivity is the most common toxicity and can manifest as allergy (clinical allergy with drug inactivation), allergic-like reaction (clinical allergy without drug inactivation) and silent inactivation (SI) (drug inactivation without any associated symptoms). Certain genetic polymorphisms have been linked to ASP-associated pancreatitis and hypersensitivity. To assess the effectiveness of ASP, the gold standard technique is the determination of serum asparaginase activity (SAA). A level ≥ 100 IU/L defines a SAA in therapeutic range. Against this background, we hypothesise that: the analysis of genetic polymorphisms related to ASP toxicity could identify patients at higher risk of pancreatitis or allergy; the incidence of allergy in paediatric patients receiving a sequential ASP scheme (native E. coli-ASP followed by PEG-ASP) could be higher than those receiving only PEG-ASP within the same clinical protocol and, finally, that the lowest dose of PEG-ASP (1,000 IU/m2) could achieve sufficient SAA levels for clinical effectiveness. To answer these hypotheses, we focused on the following objectives: to study the correlation between polymorphisms in the asparagin synthetase gene (ASNS) related to ASP toxicity in a series of paediatric patients with ALL and to compare the incidence of clinical allergy in paediatric patients with ALL who have received different ASP administration schemes in the same therapeutic protocol. In our study population, the rs3757676 and rs3832526 polymorphisms, previously described as risk and protective haplotypes of the ASNS gene for allergy and pancreatitis, were not clearly associated with the occurrence of these toxicities. The risk of ASP allergy was associated with both receiving a high-risk relapse protocol and being of Latin American ethnicity. The risk of pancreatitis was associated with age ≥ 10 years at diagnosis. In our LAL/SEHOP-PETHEMA 2013 treatment protocol, first-line use of PEG-ASP was associated with lower incidence of clinical allergy than that observed with sequential use of native E. coli-ASP followed by PEG-ASP. PEG-ASP at a dose of 1,000 IU/m2 intramuscularly was effective in achieving sufficient SAA in more than 90% of patients. The incidence of silent inactivation in patients treated with PEG-ASP first-line was very low. We detected a significant association between SAA levels and increased serum ammonium levels, decreased albumin levels, and increased triglyceride levels. No significant differences in the incidence of pancreatitis were observed depending on the ASP formulation used.

[cat] El càncer infantil és una de les principals causes de mortalitat durant la infància i l’adolescència. Segons l’Associació Espanyola contra el càncer, 1500 nens/es de 0 a 14 anys són diagnosticats anualment d’aquesta malaltia. Els tipus de càncer més freqüent són les leucèmies (28,8%), els tumors del sistema nerviós central (24%), els limfomes (11,2%) i altres tipus (36%). L'augment de la taxa de supervivència dels infants tractats de càncer ha augmentat en les últimes dècades. Aquesta major supervivència ha anat acompanyada d'un increment de les seqüeles en la dentició permanent. A diferència dels adults, el càncer infantil té una incidència molt més baixa, no es pot prevenir ni detectar per cribratge, requereix de teràpies diferents i respon als tractaments de manera molt diversa. El nostre objectiu era correlacionar el tipus de teràpia contra el càncer administrada als pacients durant la primera infància (0-5 anys) versus les seqüeles dentals registrades en supervivents (12-18 anys). Es va dur a terme un estudi de cohorts retrospectiu i unicèntric a l’Hospital Materno- Infantil Sant Joan de Déu (HSJD) de Barcelona. Es va analitzar una mostra de cent nou pacients de 12-18 anys, que havien rebut tractament contra el càncer durant la primera infància (0-5 anys). Van ser examinats aleatòriament i agrupats segons el diagnòstic i la teràpia anticancerosa rebuda. Determinar si el tipus de teràpia es correlacionava amb el nombre i la gravetat de lesions dentals que presentaven en l'adolescència. Vam proposar una nova classificació de les seqüeles dentals basada en la gravetat d’aquestes: i) lesions lleus (defectes del desenvolupament de l’esmalt i taurodontisme), ii) moderades (microdòncia), iii) lesions severes (agenèsia i escurçament radicular de més del 50%). El 85.3% dels pacients mostraven algun tipus de seqüela dental. La microdòncia va ser l'alteració dental més prevalent (52.3%), seguida dels canvis radiculars (45.9%), els defectes del desenvolupament de l’esmalt (31.2%), l’agenèsia (27.5%) i el taurodontisme (17.4%). Els agents alquilants juntament amb els alcaloides vegetals van ser els fàrmacs més administrats. Els pacients tractats amb agents alquilants tenien una major incidència d'agenèsia (p =0.02), alteracions radiculars (p=0.038) i microdòncia (p=0.001). Aquells que van rebre inhibidors de la topoisomerasa i antibiòtics citotòxics van mostrar una proporció més alta d'alteracions radiculars (p=0.039) i agenèsia (p=0.05). El tractament amb agents alquilants va presentar un risc relatiu 3.36 (1.18- 9.60) vegades més alt de presentar lesions moderades i de 2,29 (1,07-4,91) de lesions severes. Els inhibidors de la topoisomerasa i els antibiòtics citotòxics presenten un risc relatiu 1.6 (1.07-2.38) i 2.08 (1.02-4.26) vegades més alts d'alteracions radiculars i agenèsia respectivament. No vam poder demostrar cap correlació significativa entre la dosi de radiació acumulada i el nombre/tipus de lesions dentals. La majoria dels supervivents de càncer durant la primera infància van tenir almenys una seqüela dental. El nombre de lesions dentals disminueix de forma significativa a mesura que augmenta l’edat d’inici del tractament oncològic. Els infants que havien iniciat el tractament pel càncer abans dels 3 anys varen tenir el doble de risc de presentar lesions dentals. L’única alteració dental que va demostrar una associació significativa amb la durada del tractament va ser la microdòncia. El tractament amb agents alquilants juntament amb antibiòtics citotòxics i inhibidors de la topoisomerasa tenen un major risc relatiu de microdòncia, agenèsia i escurçament radicular., [eng] The increase in survival rates in children treated for cancer has been accompanied by a rise in sequelae in the permanent teeth. Our objective was to correlate the type of cancer therapy administered to patients during early childhood (0-5 years) and the dental sequelae recorded in survivors (12-18 years). In this single-center, Hospital Sant Joan de Déu (UB), a retrospective cohort study was performed. 109 patients aged 12-18 years who had received cancer treatment during early childhood (0-5 years) were randomly examined and grouped according to diagnosis and cancer therapy received. The type of therapy was correlated with the number and severity of dental lesions they presented in adolescence, according to a new classification proposed by the authors. Dental sequelae of some kind were present in 85.3% of patients. Microdontia was the most prevalent dental alteration (52.3%), followed by root changes (45.9%), enamel developmental defects (31.2%), agenesis (27.5%) and taurodontism (17.4%). Patients treated with alkylating agents had a higher incidence of agenesis (p =0.02), root changes (p=0.038) and microdontia (p=0.001). Those who received topoisomerase inhibitors and cytotoxic antibiotics showed a higher proportion of root alterations (p=0.03) and agenesis (p=0.05). Treatment with alkylating agents presented a 3.36 (1.18-9.60)-times higher relative risk of presenting moderate lesions and a 2.29 (1.07-4.91) of presenting severe ones. Topoisomerase inhibitors and cytotoxic antibiotics presented a relative risk of 1.6 (1.07-2.38) and 2.08 (1.02-4.26) of root alterations and agenesis respectively. No significant correlation between cumulative radiation dose and number/type of dental lesions could be demonstrated. Most childhood cancer survivors had at least one dental sequela. Treatment with alkylating agents together with cytotoxic antibiotics and topoisomerase inhibitors has a higher relative risk of microdontia, agenesis and root shortening.

[eng] BACKGROUND: High-risk neuroblastoma (NB) represents a heterogeneous group of tumors, whereby patients can display response to treatment and long-term outcome or develop early progressive, chemoresistant disease with poor outcome. To date, high-risk NB patients are generally treated uniformly with no further stratification, as established in routinely used risk stratification systems. A revised molecular risk stratification has been proposed based on the analysis of telomere maintenance mechanisms, and RAS or TP53 pathway mutations. However, genetics underlying this aggressive subgroup is still greatly unknown and risk stratification of high-risk NB tumors is still challenging. AIM: To study high-risk NB tumors and to define a subgroup of high-risk NB patients with particularly poor outcome, with the aim of improving risk­ stratification of high-risk NB, of identifying altered biological pathways that may represent therapeutic options, and to learn more about the biology underlying this malignant pediatric tumor. METHODS: We analyzed DNA methylation microarray and gene expression data from nearly 700 high-risk NB samples obtained at diagnosis. Cox-regression models and Machine-Learning analysis were used for survival analyses. Survival curves were estimated by Kaplan-Meier method and compared by log-rank test. Pathway analysis was performed using R package KEGGREST, ConsensusPathDB-MaxPlanck and R package topGO. Pyrosequencing, phospho-kinase array, immunoblotting and immunohistochemical techniques were used for validation purposes. RESULTS: We identified distinct DNA methylation profiles within high-risk NB. Cox­ regression models and Machine Learning analysis, identified differentially methylated CpG sites that defined two subgroups of patients with substantially different overall survival (OS). Moreover, we identified methylation markers that could distinguish these clinically relevant subgroups of tumors. Integrative analysis of DNA methylation and matching gene expression data, identified differential expression of genes involved in cellular metabolism, purine biosynthesis and AKT/mTOR cell signaling. Protein expression analysis identified high levels of proteins involved in IMP metabolism and increased activation of AKT/mTOR pathways in highly aggressive NB. CONCLUSION: We have identified (epi)genetic changes underlying the heterogeneous behavior of aggressive NB, and revealed altered pathways of interest for potential therapeutic options. We identified a set of markers that enabled classification of high-risk NB into clinically relevant subgroups., [spa] 1. OBJETIVO GLOBAL: En neuroblastoma (NB), la presencia de enfermedad diseminada en pacientes mayores de 18 meses de edad o la presencia de amplificación del oncogén MYCN a cualquier edad, define un grupo de alto-riesgo clínico con supervivencia a 5 años inferior a 50%. El NB de alto-riesgo representa un grupo heterogéneo de tumores, con comportamiento clínico diverso y diferente respuesta al tratamiento. Sin embargo, los pacientes con tumores diseminados de alto-riesgo son tratados uniformemente con tratamiento multimodal intensivo, sin ninguna estratificación adicional. En la actualidad, no existen biomarcadores que permitan identificar, de forma rápida y precisa en el momento del diagnóstico, los pacientes con NB agresivos, potencialmente refractarios, que no se benefician de los tratamientos convencionales y que necesitan nuevas estrategias terapéuticas. Numerosos estudios han demostrado que el análisis del perfil de metilación del DNA permite tipificar y clasificar de forma precisa los tumores del sistema nervioso central, demostrando ser aplicable en el contexto del diagnóstico molecular. Hasta la fecha, el metiloma del HR-NB, no ha sido estudiado en profundidad. En esta tesis doctoral, hemos estudiado el metiloma del HR-NB con el objetivo de i) identificar patrones de metilación que permitan distinguir subgrupos con diversa evolución clínica, y mejorar la estratificación de los pacientes, ii) identificar posibles vías biológicas alteradas que puedan representar nuevas opciones terapéuticas, y iii) mejorar el conocimiento de la biología subyacente al comportamiento agresivo de estos tumores. 2. OBJETIVOS ESPECÍFICOS: l. Estudiar el perfil de metilación del DNA en el neuroblastoma de alto­ riesgo. 2. Identificar potenciales biomarcadores epigenéticos asociados con supervivencia de los pacientes con neuroblastoma de alto-riesgo. 3. Caracterizar la biología del neuroblastoma de alto-riesgo.

Diffuse Intrinsic Pontine Glioma (DIPG) is a universally fatal paediatric brainstem tumour with a median overall survival of 9-11 months. The unique genetic, anatomical and developmental identity of the tumour means that there are currently no effective chemotherapies or targeted therapies. This thesis aimed to identify and characterise novel targets for the treatment of DIPG. Potential therapeutic opportunities arise from the frequent mutations found in histone H3 (H3K27M) and kinase ACVR1 found in DIPG tumours. A screen of epigenetic protein inhibitors revealed that the viability of the patient-derived DIPG cell line HSJD-DIPG-007 was highly sensitive to arginine methyltransferase (PRMT) inhibitors, particularly in ACVR1 mutant lines. The PRMT5 inhibitor LLY-283 was identified as the most promising lead for its potent inhibition of DIPG viability and the recognised role of PRMT5 in the regulation of the cell cycle and stemness. RNA-sequencing and phenotypic analyses revealed that LLY-283 did not induce cell death, but reduced stemness and invasiveness, altered metabolism and restored H3K27me3 levels in DIPG cells. Through collaboration with Ángel Montero Carcaboso, LLY-283 was tested in an orthotopic murine xenograft model of DIPG. LLY-283 reduced infiltration of DIPG cells into the murine forebrain, but did not prolong survival, perhaps reflecting inadequate drug exposure. In parallel, the CRISPR/Cas9 system was used to correct the causative G328V ACVR1 mutation in DIPG cells. The resultant isogenic DIPG cells demonstrated slowed proliferation after correction of ACVR1 mutations, rather than a complete growth arrest as observed with published shRNA mediated ACVR1 knockdown. Surprisingly, the isogenic cell lines also showed comparable sensitivity (GI50) to PRMT5 and ACVR1 inhibition, suggesting other genetic differences contribute to the variation in treatment sensitivity between DIPG cell lines. My findings highlight the value of isogenic DIPG cell lines for interrogating the effects of individual tumorigenic mutations. It remains incredibly challenging to develop new strategies to treat DIPG. This thesis supports the future design of combination treatments for DIPG and provides new experimental tools to aid their development.

[eng] Therapy development in cancer involves several consecutive steps including (1) the identification of the unmet medical need (disease or clinical question), (2) the establishment of clinically relevant resources or models to address such need, (3) the evaluation of therapies or experimental questions in the established models, and (4) the design and execution of clinical trials or protocols. The ambition of my PhD work was to follow the mentioned steps to build a body of results with potential clinical impact in the pediatric oncology field. Research at our institution, SJD, focuses on several types of cancers with bad prognosis, such as pediatric sarcomas. These cancers belong to a rare and heterogeneous group of skeletal and soft tissue malignancies accounting for approximately 12% of all childhood solid tumors. The most frequently occurring ones are Ewing sarcoma, osteosarcoma and rhabdomyosarcoma. With the up-to-date treatment modalities, based on surgery, radiation and chemotherapy, the 5-year survival rates of these patients have improved up to 70-80% in the last decades. However, a substantial proportion of patients relapse and do not respond consistently to rescue therapy. Whether the lack of response to therapy of these patients is due to drug delivery issues in resistant tumor cells is not completely understood. The main question I wanted to address in my work was whether patients whose tumors stop responding to anticancer medicines show diminished intratumoral drug distribution. Because this experimental question was challenging to address in the clinical setting, we needed to generate the adequate laboratory models. Thus, we established PDX models in immunodeficient mice. There is compelling evidence suggesting that PDX, at least at initial passages, reproduce the clonal heterogeneity, genetics and histology of several types of cancer. Whether this holds true for pediatric sarcomas was not sufficiently clear. Thus, we embraced an ambitious project to address (1) the identification of clinical and technical factors involved in pediatric sarcoma PDX engraftment, (2) the characterization of the stability of the PDX during initial passages, and (3) the relationship between successful PDX and patient prognosis. The main hypotheses of my work were: (1) PDX models faithfully represent pediatric sarcoma tumors established from patients at different disease stages. PDX conserve the main histology, molecular and functional properties of human tumors over successive passages in mice. (2) PDX engraftment correlates with patient prognosis. Successful establishment of PDX models helps identify patients with higher risk of recurrence and disease progression. (3) Intratumoral distribution of anticancer drugs becomes restricted due to the evolution of patient disease. Cancer cells in relapsed tumors displace chemotherapeutics from the intracellular to the extracellular tumor compartment. (4) The expression of multidrug resistance efflux transporters explains, at least partially, the shift of the intratumoral drug distribution towards the extracellular compartment upon tumor evolution in relapsed patients. To address my hypotheses, the main objectives of my thesis were: (1) To establish and characterize PDX models from biopsies and necropsies of pediatric patients diagnosed with Ewing sarcoma, osteosarcoma and rhabdomyosarcoma. To address this goal, we implanted patient samples obtained at Hospital Sant Joan de Déu in immunodeficient mice. Upon successful engraftment as PDX, we characterized the histology, genomics and response to model therapy (irinotecan) of the established tumor models over time in successive passages in mice. (2) To identify factors favoring PDX engraftment and to study the association between PDX engraftment and prognosis in pediatric patients with Ewing sarcoma, osteosarcoma and rhabdomyosarcoma. To address this goal, we collected clinical and technical data from the patients and the PDX, and we studied the relationship between PDX engraftment and several patient and sample factors, including disease stage (diagnosis or relapse) and patient outcome (event free survival and overall survival). (3) To detect and characterize changes in anticancer drug activity and intratumoral drug distribution during the evolution of Ewing sarcoma. To address this goal, we established pairs of PDX models from patients at diagnosis and late disease stages. In such paired PDX, we studied the activity and distribution of the model drug irinotecan and its active metabolite, SN-38. We applied the intratumoral microdialysis – tumor homogenate technique to obtain samples of PDX engrafted in mice receiving irinotecan infusions, and we calculated the unbound volume of distribution of SN-38 in the established PDX. We analyzed the expression and function of multidrug resistance efflux transporters, such as P-glycoprotein, as likely cause of the limited drug distribution and acquisition of resistance in relapsed tumors.

Last advances in the treatment of pediatric tumors has led to an increase of survival rates of children affected by primitive neuroectodermal tumors, however, still a significant amount of the patients do not overcome the disease. In addition, the survivors might suffer from severe side effects caused by the current standard treatments. Oncolytic virotherapy has emerged in the last years as a promising alternative for the treatment of solid tumors. In this work, we study the anti-tumor effect mediated by the oncolytic adenovirus VCN-01 in CNS-PNET models. VCN-01 is able to infect and replicate in PNET cell cultures, leading to a cytotoxicity and immunogenic cell death. In vivo, VCN-01 increased significantly the median survival of mice and led to long-term survivors in two orthotopic models of PNETs. In summary, these results underscore the therapeutic effect of VCN-01 for rare pediatric cancers such as PNETs, and warrants further exploration on the use of this virus to treat them.

Burkitt-like lymphoma with 11q aberration is characterized by pathological features and gene expression profile resembling those of Burkitt lymphoma but lacks the MYC rearrangement and carries an 11q-arm aberration with proximal gains and telomeric losses. Whether this lymphoma is a distinct category or a particular variant of other recognized entities is controversial. To improve the understanding of Burkitt-like lymphoma with 11q aberration we performed an analysis of copy number alterations and targeted sequencing of a large panel of B-cell lymphomarelated genes in 11 cases. Most patients had localized nodal disease and a favorable outcome after therapy. Histologically, they were high grade B-cell lymphoma, not otherwise specified (8 cases), diffuse large B-cell lymphoma (2 cases) and only one was considered as atypical Burkitt lymphoma. All cases had a germinal center B-cell signature and phenotype with frequent LMO2 expression. The patients with Burkitt-like lymphoma with 11q aberration had frequent gains of 12q12-q21.1 and losses of 6q12.1-q21, and lacked common Burkitt lymphoma or diffuse large B-cell lymphoma alterations. Potential driver mutations were found in 27 genes, particularly involving BTG2, DDX3X, ETSI , EP300, and GNA13. However, ID3, TCF3, or CCND3 mutations were absent in all cases. These results suggest that Burkitt-like lymphoma with 11q aberration is a germinal center-derived lymphoma closer to high-grade B-cell lymphoma or diffuse large B-cell lymphoma than to Burkitt lymphoma. This work was supported by Asociacion Espanola Contra el Cancer (AECC CICPFI6025SALA), Fondo de Investigaciones Sanitarias Instituto de Salud Carlos III (Miguel Servet program CP13/00159 and PI15/00580, to IS), Spanish Ministerio de Economia y Competitividad, Grant SAF2015-64885-R (EC), Generalitat de Catalunya Suport Grups de Recerca (2017-SGR-1107 I.S. and 2017-SGR-1142 to EC), and the European Regional Development Fund "Una manera de fer Europa". JERZ was supported by a fellowship from the Generalitat de Catalunya AGAUR FI-DGR 2017 (2017 FI_B01004). EC is an Academia Researcher of the "Institucio Catalana de Recerca i Estudis Avancats" (ICREA) of the Generalitat de Catalunya. This work was developed at the Centro Esther Koplowitz, Barcelona, Spain. The group is supported by Accio Instrumental d'Incorporacio de Cientifics i Tecnolegs PERIS 2016 (SLT002/16/00336) from the Generalitat de Catalunya.

[eng] Pediatric RMS is a developmental tumor that affects patients from birth to late adolescence. RMS tumorigenesis involves the stalk of embryological myogenic processes. Classically, two main subgroups of RMS have been defined based on the histopathological features: Embryonal (ERMS) and Alveolar (ARMS). However, the molecular classification refines the subgrouping into Fusion Positive or Fusion Negative based on the occurrence of FOXO1 oncogenic translocations. The recent genetic and epigenetic landscapes of those subgroups have identified few potential druggable targets. Nowadays, the outcome of children with relapsed/refractory RMS remains very poor. In order to find new opportunities for these patients this thesis focuses on the identification of new therapeutic targets effective for RMS treatment as well as on characterizing biomarkers of response for the new targeted treatment. We initially performed a functional approach starting from IGF1R target therapies to main downstream pathways including PI3K/AKT/mTOR and MEK/ERK that we found active in primary samples as well as in patient derived models. The new IGF1/2 monoclonal antibody m708.5 was found active in a subset of RMS particularly dependent on the IGF/AKT/mTOR pathway. Interestingly, we found that the ATP-competitive pan-AKT inhibitor Ipatasertib was highly active causing tumor regression in a subset of patient derived models. We were able to classify RMS primary models and their parental samples into two subgroups: Ipatasertib- dependent and Ipatasertib non-dependent. Moreover, preclinical pharmacology corroborated the dose-dependent response of RMS to this inhibitor. Most interesting, those tumors particularly sensitive to Ipatasertib were shown to be resistant to the MEK inhibitor Trametinib. Surprisingly, the study of a mechanistically different AKT inhibitor did not recapitulate Ipatasertib efficacy in vivo. We discovered that Ipatasertib sensitivity correlated with high PRKG1 levels. We described for the first time PRKG1 gene expression as RMS specific and predictive of Ipatasertib response in vivo. The genetic signature of PRKG1 depleted RMS cells is enriched in the expression of myogenic genes, positioning for the first time PRKG1 in the landscape of RMS tumorigenesis. The potential of PRKG1 as a prognostic marker was evaluated. Ongoing studies will determine the mechanism of myogenic blocking dependent on PRKG1.

B-cell non-Hodgkin lymphoma (B-NHL) of pediatric and young adult population is a diverse group of neoplasms predominantly composed of aggressive B-cell lymphomas from the germinal center (GC). Molecular characterization of pediatric series has allowed the identification of several subtypes that predominantly occur in this subgroup of age. Despite of that, genomic features of these pediatric entities and their relationship to other B-NHL in this group of patients have not been extensively investigated. This thesis has aimed to address this gap of knowledge by performing a genetic and molecular characterization of large series of pediatric and young adult variants of GC-derived B-NHL including the Burkitt- like lymphoma with 11q aberration (BLL-11q) , pediatric type follicular lymphoma (PTFL) and large B-cell lymphomas (LBCL) such as diffuse large B-cell lymphomas (DLBCL) , high grade B- cell lymphomas, not otherwise specified (HGBCL, NOS) and large B-cell lymphoma with IRF4 rearrangement (LBCL-IRF4) entities. In the Study 1 we have molecularly characterized a series of 11 BLL-11q observing that BLL- 11q differed clinically, morphologically and immunophenotypically from conventional BL and instead showed features more consistent with HGBCL or DLBCL. Genomic profile was also different from that of BL and DLBCL with a mutational landscape characterized by the lack of typical BL mutations in ID3, TCF3, or CCND3 genes and recurrent specific BTG2 and ETS1 mutations, not present in BL but in germinal center B-cell (GCB) DLBCL subtype. All these observations suggest that BLL-11q is a neoplasm closer to other GC-derived lymphomas rather than BL. In Study 2, we expanded our knowledge on the genetic alterations associated to PTFL by verifying the presence of MAP2K1 and IRF8 mutations in a previously well characterized series of 43 PTFL. We demonstrate the activating effect of MAP2K1 mutations by immunohistochemical analysis observing phosphorylation of the MAP2K1 downstream target extracellular signal-regulated kinase in those mutated cases. Besides, we demonstrate the specificity of MAP2K1 and IRF8-K66R mutations since they are absent in conventional FL or in t(14;18)-negative FL. Finally, in the Study 3 we characterized a large series of LBCL including DLBCL, HGBCL, NOS and LBCL-IRF4 through an integrative analysis including targeted next generation sequencing, copy number, and transcriptome data. Results showed that each subgroup displayed different molecular profiles. LBCL-IRF4 had frequent mutations in IRF4 and NF-κB pathway genes (CARD11, CD79B) whereas DLBCL, NOS was predominantly of GCB-DLBCL subtype and carried gene mutations similar to the adult counterpart (e.g., SOCS1 and KMT2D). A subset of HGBCL, NOS displayed recurrent alterations of BL-related genes such as MYC, ID3, CCND3 and SMARCA4, whereas other cases were genetically closer to GCB-DLBCL. Interestingly, we could identify age-related differences in pediatric DLBCL since pediatric and young adult cases were mainly of GCB subtype, displayed low genetic complexity and virtually lacked primary aberrations (BCL2, MYC and BCL6 rearrangements). Finally, we identify clinical and molecular features related to unfavorable outcome such as age >18 years, high LDH levels, activated B-cell (ABC) DLBCL profile, high genetic complexity, homozygous deletions of 19p13.3/TNFSF7/TNFSF9, gains of 1q21-q44/MDM4/MCL1 and TP53 mutations. Altogether, we conclude that GC-derived B-NHL of pediatric and young adult population is a heterogeneous group of tumors including different entities with specific molecular profiles and clinical behavior. This thesis has contributed to increase the knowledge of these lymphoma entities identifying biomarkers that might be helpful to improve their diagnosis and to design management strategies more adapted to their particular biological behavior.

This bachelor thesis focuses on oncological diseases in children and adolescents. It deals with differences between pediatric patients and adults, what are the causes of their malignant diseases, prevention, symptoms and treatment. In the practical part I focused on radiation therapy in children, using photon beam and proton beam, their advantages and disadvantages. I dealt with the incidence of the most common malignancies in children aged 0-19 years in the period 1996-2016. I analyzed the data from the National Cancer Registry and processed it into graphs and tables. I also looked at the data on the long-term survival of cured patients. The collected data show rather a decreasing tendency in the incidence of childhood malignancies in the monitored period 1996-2016. Tumor mortality in children has been decreasing in the period under review, after an initial sharp decline in recent years rather slightly. The higher incidence of malignancies in children aged 0-19 is in boys. I also graphically processed the age distribution of patients, where the first wave of increased incidence is recorded in the youngest patients under 4 years and the second wave in adolescents aged 15-19 years, which is different from the distribution of tumor incidence in the adult population where the risk of cancer increases with age. The relative percentage of five-year survival in pediatric cancer patients over time has increased with the development of cancer treatment and supportive care and dispenzarzation. The content of this work can serve as a basic overview of cancer of children and adolescents for health professionals and the general public.

Neuroblastoma (NB) is the most common extracraneal solid tumor diagnosed in the first 5 years of childhood and accounts for approximately 15% of all pediatric cancer-related deaths. At the time of diagnosis, about half of NB patients present disseminated disease, being the bone marrow (BM) the most common site of dissemination. The persistence of infiltrated BM during treatment or relapse is predictive of patient poor outcome. The BM microenvironment has unique biologic properties that favor progression of disseminated NB tumor cells. In this environment, the receptor CXCR4 has a pivotal role for BM homeostasis and is involved in metastatic dissemination in several cancers. In NB, CXCR4 is expressed in tumor cells; however, its oncogenic role in relation with its ligand CXCL12 has shown contradictory results. Using an in vitro model that recapitulates low oxygen levels and chemokine signaling present in the BM environment, we explored whether CXCR4 together with MIF, a second ligand, is critical for NB survival and proliferation in the niche. We also evaluated MIF inhibition as a therapeutic option for NB. To develop a BM-based in vitro model, NB cells were cultured in different conditioned media (CMs) derived from supernatants of patient-derived BM primary cells (CM-BM) and NB cell lines (CM-NB) cultured alone, or in combination (CM-BM/NB). To mimic BM oxygen levels, NB cells were cultured under hypoxia (1% O2), as compared to cell culture normoxia (21% O2). Expanded BM cultures used to generate CMs contained a heterogenic population with a predominant cellularity positive for mesenchymal stromal markers measured by flow cytometry. Cytokine arrays and ELISA assays of CMs revealed MIF as the highest NB released cytokine, whereas CXCL12 was not detected. The expression of MIF and CXCL12 signaling pathways was analyzed with different public NB databases. Among the analyzed genes, the high expression of CXCR4 and MIF was associated with patient poor outcome and high-risk disseminated staging. To further explore the role of CXCR4/MIF axis in high- risk disseminated NB, in vitro and in vivo functional studies were performed with or without the covalent MIF inhibitor 4-IPP and the CXCR4 antagonist AMD3100. When exposed to BM-derived CMs and hypoxia, BM-derived NB cell lines showed increased surface expression of CXCR4 by flow cytometry. The same culture condition increased phosphorylated levels of AKT/PI3K and ERK/MAPK measured by western blot. Cell viability assays showed that hypoxic conditions and BM-derived CMs enhanced NB cell proliferation at different time points. Similarly, in vivo, the co-injection of BM cells favored NB tumor progression by reducing engraftment times in contrast to NB injection alone. Using wound healing assays and Matrigel-coated Transwells, CM-BM/NB chemoattracted and enhanced migration and invasion of LAN-1 cells cultured under hypoxic conditions. These aggressive phenotypes promoted by the BM-based model were reverted by adding sub-lethal concentrations of the MIF inhibitor 4-IPP. We also explored whether MIF present in our CMs affected response to chemotherapy. After treatment with doxorubicin and etoposide at IC50 values LAN-1 cell viability increased in CM-BM/NB compared to control media. In both cases, chemo-sensitivity was restored when 4-IPP was added to CM-BM/NB. Finally, the administration of 4-IPP delayed the tumor progression and increased mice survival in a LAN- 1 subcutaneous xenograft model. In conclusion, our findings provide new understanding of the contribution of BM microenvironment to NB progression. Based on our BM-model, the relationship between the BM microenvironment and NB cells appears mediate, in part, by the autocrine CXCR4/MIF signaling axis. Furthermore, our results suggested that MIF could represent a therapeutic target for the treatment of patients with high-risk NB.

[eng] Neuroblastoma (NB) is a devastating paediatric cancer that originates in the developing sympathetic nervous system. These tumours account for 40% of the cases of cancer diagnosed during the first year of life and 8% of the cases detected overall during childhood. They show a striking clinical diversity, ranging from spontaneous remission to fatal metastatic dissemination. To optimize therapeutic approaches, NB patients have been stratified into risk groups. For the high risk (HR} patients, the 5 years overall survival probability remains below 30-40%. The failure to successfully treat these HR patients mainly results from the therapy-resistance and metastatic potential harboured by these tumours. The large intra-tumour heterogeneity of the HR tumours seems to be a key factor contributing to tumour progression. Thereby, there is an urgent need to understand the biological diversity of the HR-NBs in order to develop efficient therapies for these patients. lnterestingly, NBs show a marked scarcity of recurrent genetic changes even during relapse, pointing towards a relevant role of non-genetic sources of tumour heterogeneity. Compelling evidences suggest the existence of cells possessing a tumour-propagating capacity, called cancer stem cells or tumour-propagating cells (eses/TPes}, in these HR-NB tumours. Defining the heterogeneity of NBs and their CSCs: their self-renewal ability. The general aim of this doctoral thesis was to identify a genetic signature for neuroblastoma cancer stem cells (NBcsc), with the ultimate goal of providing new specific molecular markers of these NBcsc and candidate genes that might be useful for the development of future therapeutic strategies targeting the NBcsc in HR-NBs. lt is assumed that NBcsc share many similarities with their normal stem cells counterparts, the neural crest cells (NCCs), which represents transient embryonic population of pluripotent stem cells that give rise to the peripheral nervous system. Therefore, we compared the transcriptomic signature of NCCs with the transcriptomic profiles established for clinically relevant groups of NB patients. Among the candidates identified by our double screening, we retrieved Neurexophilin 1 (NXPHl }: an extracellular glycoprotein known to bind to the transmembrane receptors of the alpha-Neurexin (a-NRXN) family. To determine whether NXPHl/a-NRXNs activity is effectively related to NBcsc, we analysed their expression in a panel of human NB cell lines in conditions of stem cell enrichment. The marked induction of a-NRXNl/2 mRNA levels in the stem cell-enriched fraction suggested that they might be NBcsc markers. We identified the existence of a low subpopulation of a-NRXNl+ cells in samples from human NB cell lines and patient-derived xenografts. We further established that these a-NRXNl+ cells represents functionally discrete subpopulation of NB cells characterized by: 1} an active cycling behaviour, 2} an increased self-renewal capacity, and 3) a higher probability to survive upon chemotherapeutic insult. Our data suggest that these a-NRXNl+ NB cells are endowed with a tumour-propagating capacity and that they are required to sustain tumour growth in vivo. In parallel, we investigated whether NXPH1 is implicated in NB malignancy. Our data revealed that NXPH1 promotes NB growth, possibly by stimulating the proliferation of actively dividing NB cells and by increasing the proportion of NB cells expressing the NCC stem cell marker p75NTR. Finally, we showed that inhibiting NXPH1 or a-NRXN1 activity abrogates NB tumour growth in xenograft models. Our work provides the first experimental evidence that NXPH1, probably acting through its receptor a-NRXN1, exerts a functional role in NB progression. We suggest that NXPH1, present in the tumour microenvironment, controls the tumour-propagating capacity of NBcsc and that its reduced activity might facilitate the malignant progression of these tumours by enabling NBcsc to acquire a metastatic capacity., [spa] El neuroblastoma (NB) es un tumor pediátrico del sistema nervioso simpático en desarrollo. La probabilidad de supervivencia de los pacientes de alto riesgo no supera el 30-40%. El estudio de la heterogeneidad celular del NB revela la probable existencia de células con capacidad de propagación tumoral (en inglés cancer stem cells, CSCs). Su identificación y caracterización es fundamental en la búsqueda de nuevos fármacos para dichos pacientes. El objeto de esta tesis doctoral ha sido la identificación de la huella genética de las CSCs en el NB con la finalidad de identificar marcadores moleculares específicos y nuevas dianas terapéuticas. Para ello, partimos de la premisa de que las CSCs de los NBs deben de compartir ciertas características con sus equivalentes en el tejido sano, las células de la cresta neural (en inglés neural crest cells, NCCs), una población embrionaria de células madre que origina el sistema nervioso periférico. Al comparar el transcriptoma de las NCCs con el extraído de una comparación entre grupos de pacientes con relevancia clínica, seleccionamos la Neurexofilina 1 (NXPHl), un ligando extracelular de las Neurexinas alfa (a-NRXN). Para determinar si ambos están relacionados con el fenotipo de eses, analizamos su expresión en una colección de líneas celulares en condiciones de enriquecimiento para dicho fenotipo. El marcado aumento en los niveles de RNA mensajero de a-NRXNl/2 sugirió que podrían fun­ cionar como marcadores de las CSCs . Hemos confirmado la existencia de una población a-NRXNl+ caracterizada por una mayor capacidad de proliferación, de replicación y de pervivencia a quimioterapia. Las células a-NRXNl+ presentan características de eses y son requeridas para el crecimiento tumoral. En paralelo vemos que NXPHl promueve el crecimiento tumoral estimulando la proliferación y la presencia de células p75NTR+, marcador asociado a las NCCs . Además, la inhibición de NXPHl o a-NRXNl impide el crecimiento tumoral en modelos experimentale . Este trabajo constituye la primera evidencia funcional del papel de NXPHl en la progresión del NB. Sugerimos que NXPHl , probablemente a través de a-NRXNl, participa en la regulación de la capacidad de propagación tumoral y que su pérdida favorece la adquisición de rasgos asociados a pacientes de alto riesgo.

Treballs Finals de Grau de Farmàcia, Facultat de Farmàcia i Ciències de l'Alimentació, Universitat de Barcelona, 2019, [eng] Radiation therapy is one of the most effective tools in the treatment of malignant tumours and is applied to both adults and children who suffer from primary or metastatic brain tumours. However, in the treatment of paediatric malignancies is responsible of severe late effects, such as hormonal imbalances, growth retardation and cognitive decline. Alleviating these late effects could have a huge impact in the quality of life of the increasing number of children who survive their cancer. Our aim was to investigate the possible protective effect in the brain of montelukast (MTK). Female mice received a double dose of 4 Gy to the whole brain separated by 12 h in between on postnatal day 21 (P21) and were sacrificed 12 days later. For cell count we looked at oligodendrocytes (Olig2+ cells) in the corpus callosum (CC) and at proliferating cells (Ki-67+ cells) in the hippocampus (HC). A difference after irradiation (IR) was observed in the Olig2+ count, where non-IR mice showed higher numbers of oligodendrocytes compared with IR animals (P < 0.01). IR also affected the density of these cells (P < 0.05), but in no case was there a significant difference between IR NaCl and IR MTK groups. In the HC there was a significant reduction of MTK cells versus NaCl control cells (P < 0.05). Therefore, further studies are needed. In conclusion, we show that MTK does not protect neither against Olig2+ cell loss in the CC nor Ki-67+ loss in the HC after IR and that MTK lowers the number of proliferating cells in the HC regardless IR., [spa] La radioteràpia és una de les eines més efectives en el tractament de tumors malignes i s’aplica tant a adults com a infants que pateixen tumors primaris o metastàtics. No obstant, en el tractament pediàtric és responsable d’efectes retardats severs com descompensacions hormonals, retard del creixement i declivi cognitiu. Alleugerar aquests efectes podria tenir un gran impacte en la qualitat de vida del creixent nombre de nens que sobreviuen a la malaltia. El nostre objectiu era investigar el possible efecte protector en el cervell del montelukast (MTK). Ratolins femella van rebre una doble dosis de 4 Gy a tot el cervell separada per 12 h entremig, en el dia postnatal 21 (P21) i van ser sacrificades 12 dies després. Pel comptatge de cèl·lules vam mirar el oligodendròcits (Olig2+ cells) en el cos callós (CC) i les cèl·lules proliferatives (cèl·lules Ki-67+) a l’hipocamp (HC). Es va observar una diferència després de la irradiació (IR) en el comptatge d’Olig2+ la qual mostrava que els ratolins no irradiats tenien un major nombre d’oligodendròcits comparat amb els animals irradiats (P < 0.01). La IR també va afectar la densitat d’aquestes cèl·lules (P < 0.05), però en cap cas va haver-hi una diferència significativa entre els grups IR NaCl i IR MTK. A l’HC hi havia una reducció significativa de cèl·lules MTK versus cèl·lules NaCl dels grups de control (P < 0.05). Per tant, es requereixen més estudis. Com a conclusió, mostrem que el MTK no protegeix ni contra la pèrdua de cèl·lules Olig2+ en el CC ni contra la pèrdua de cèl·lules Ki-67+ en l’HC després de la radioteràpia i que el MTK disminueix el número de cèl·lules proliferant en l’HC independentment de la IR.

Introduction Cancer and blood disorders in children are rare. The progressive improvement in survival over the last decades largely relies on the development of international academic clinical trials that gather the sufficient number of patients globally to elaborate solid conclusions and drive changes in clinical practice. The participation of Spain into large international academic trials has traditionally lagged behind of other European countries, mainly due to the burden of administrative tasks to open new studies, lack of financial support and limited research infrastructure in our hospitals. Methods The objective of ECLIM-SEHOP platform (Ensayos Clínicos Internacionales Multicéntricos-SEHOP) is to overcome these difficulties and position Spain among the European countries leading the advances in cancer and blood disorders, facilitate the access of our patients to novel diagnostic and therapeutic approaches and, most importantly, continue to improve survival and reducing long-term sequelae. ECLIM-SEHOP provides to the Spanish clinical investigators with the necessary infrastructural support to open and implement academic clinical trials and registries. Results In less than 3 years from its inception, the platform has provided support to 20 clinical trials and 8 observational studies, including 8 trials and 4 observational studies where the platform performs all trial-related tasks (integral support: trial setup, monitoring, etc.) with more than 150 patients recruited since 2017 to these studies. In this manuscript, we provide baseline metrics for academic clinical trial performance that permit future comparisons. Conclusions ECLIM-SEHOP facilitates Spanish children and adolescents diagnosed with cancer and blood disorders to access state-of-the-art diagnostic and therapeutic strategies.

Background: The aim of this study was to test the feasibility and utility of developing patient-derived orthotopic xenograft (PDOX) models for patients with malignant peripheral nerve sheath tumors (MPNSTs) to aid therapeutic interventions in real time. Patient & Methods: A sporadic relapsed MPNST developed in a 14-year-old boy was engrafted in mice, generating a PDOX model for use in co-clinical trials after informed consent. SNP-array and exome sequencing was performed on the relapsed tumor. Genomics, drug availability, and published literature guided PDOX treatments. Results: A MPNST PDOX model was generated and expanded. Analysis of the patient’s relapsed tumor revealed mutations in the MAPK1, EED, and CDK2NA/B genes. First, the PDOX model was treated with the same therapeutic regimen as received by the patient (everolimus and trametinib); after observing partial response, tumors were left to regrow. Regrown tumors were treated based on mutations (palbociclib and JQ1), drug availability, and published literature (nab-paclitaxel; bevacizumab; sorafenib plus doxorubicin; and gemcitabine plus docetaxel). The patient had a lung metastatic relapse and was treated according to PDOX results, first with nab-paclitaxel, second with sorafenib plus doxorubicin after progression, although a complete response was not achieved and multiple metastasectomies were performed. The patient is currently disease free 46 months after first relapse. Conclusion: Our results indicate the feasibility of generating MPNST-PDOX and genomic characterization to guide treatment in real time. Although the treatment responses observed in our model did not fully recapitulate the patient’s response, this pilot study identify key aspects to improve our co-clinical testing approach in real time.

Colorectal cancer is one of the most prevalent, and one of the deadliest, types of cancer in the world. The colonic epithelium is positioned atop a subepithelial structure consisting of extracellular matrix and stromal cells, and colorectal tumors closely interact with this tissue. Myofibroblasts make up the primary cellular component of the subepithelial stroma in the colon, and play important roles in the maintenance of the normal colonic stem cell niche. Increased recruitment of local myofibroblasts into the tumor bulk is a feature of some primary and metastatic colorectal cancers, and is associated with poor prognosis. The first aim of this thesis was to probe the nature of the bidirectional interaction between colorectal cancer cells and colonic myofibroblasts. Two in vitro assays integrating myofibroblasts, colorectal cancer cells, and extracellular matrix were devised to mimic the in vivo arrangement and communication between these cells. Using these assays, it was shown that myofibroblast-derived hepatocyte growth factor reduces differentiation in a subset of colorectal cancer cell lines (Chapter 3). Additionally, colorectal cancer cells were shown to recruit myofibroblasts by secreting ligands of the platelet-derived growth factor family (Chapter 4). A secondary aim of the project was to develop an analytical technique to robustly categorize colorectal cancer gene expression profiles in an unsupervised manner. Gaussian Mixture Modeling was used to generate categorized expression data for an in-house colorectal cancer cell line panel, as well as a publically available dataset from primary tumors (Chapter 5). 2x2 statistical analyses on the categorized data confirmed known genetic associations in the cancer cells, and also uncovered characteristic gene expression signatures corresponding to intratumoral heterogeneity and stromal contamination (Chapter 6). This project identifies several mechanisms responsible for the heterogeneity observed in colorectal cancer behaviors, and provides tools to probe these characteristics further both experimentally and analytically.

[spa] INTRODUCCIÓN: Vivir la experiencia de tener un hijo con cáncer es una situación que genera una crisis en la familia que afecta no sólo a nivel estructural sino también emocional. Las enfermeras son los profesionales, miembros del equipo multidisciplinar, que interrelacionan de manera específica con estas familias, por lo que es de interés saber cómo evidencian esta experiencia y su impacto en las familias. Por tal de poder mejorar la practica asistencial que debe contemplar una orientación holística dentro de los cuidados de alta complejidad que precisa un niño con enfermedad oncológica. OBJETIVOS: El objetivo principal fue comprender y analizar en profundidad la vivencia en el momento del diagnóstico de la enfermedad oncológica infantil en las familias y la percepción del fenómeno en las enfermeras. Los objetivos específicos consistieron en analizar el impacto en las familias del debut de enfermedad oncológica infantil, explorar la percepción de las enfermeras sobre el impacto y la vivencia de las familias en el inicio de una enfermedad oncológica infantil, y comparar la percepción que tienen las familias con la percepción de las enfermeras respecto el debut de la enfermedad oncológica infantil. METODOLOGÍA: Estudio cualitativo siguiendo un enfoque basado en la fenomenología hermenéutica de Heidegger cuyo ámbito de estudio fueron las unidades de Oncología y Hospital de día del Hospital Sant Joan de Déu de Barcelona. Los informantes fueron las familias de niños con cáncer y las enfermeras dedicadas a su cuidado. En la selección de dichos informantes se usó la técnica de muestreo teórico o intencionado teniendo en cuenta variables sociodemográficas que ayudaron a definir el perfil del informante en ambos grupos de estudio hasta conseguir la saturación teórica de la información. Dicha saturación se consiguió antes de acabar con el proceso de recolección de información ya que interesaba poder disponer de la visión de los diferentes perfiles de informantes de cada grupo. Para la recogida de datos se utilizó la entrevista semiestructurada siguiendo un guión de tópicos preparado previamente y el diario de campo. El tipo de análisis utilizado fue temático bajo el método de análisis del contenido, siguiendo método de análisis Guía QUAGOL (Qualitative Analysis Guide of Leuven). Se utiliza como herramienta informática el programa de Nvivo10. Al ser el análisis un proceso circular y continuo, al ir profundizando en la información recibida, se fueron cambiando o añadiendo categorías y subcategorías. RESULTADOS: Las entrevistas realizadas fueron 14 en el grupo 1 (familias) y 17 en el grupo 2 (enfermeras).En el grupo 1 (familias) se obtuvieron 1060 unidades de significado que se agruparon en 11 categorías y 9 subcategorias. En el grupo 2(enfermeras) se obtuvieron 822 unidades de significado que se agruparon en 12 categorías y 7 subcategorias. En el grupo 1(familias), se pudo observar que la categoría que obtuvo un mayor número de referencias en unidades de significado fue repercusión de la enfermedad en la familia (REPERENFER) (n=121) y, la que menos, fue cuidado del hijo enfermo (CUIDADOHIJO) (n=10) que se referia a quién se centraba en cuidar al niño enfermo de cáncer. En el grupo 2 (enfermeras), se pudo observar que la categoría que obtuvo un mayor número de referencias en unidades de significado fue emociones observadas (EMOENFER) (n=134) y la que menos, presencia de fatiga por compasión (FATIGAENFERMERA) (n=1). Los resultados de este estudio describen el impacto y la experiencia de las familias ante el inicio de la enfermedad oncológica de sus hijos. Muestran que es una experiencia difícil de vivir y que afecta a todos los niveles (económico, organizativo, emocional, social) alterando los procesos familiares. Asimismo, existe un impacto emocional que les imposibilita procesar la situación que viven, dado que el primer sentimiento que sienten es dolor y miedo ante la información que reciben sobre el diagnóstico de cáncer. Muchas veces las reacciones vividas son rabia, enfado, negación, bloqueo emocional, culpa, tristeza. También los resultados permitieron detectar que las enfermeras no sólo expusieron el cómo perciben el impacto del inicio de la enfermedad oncológica en las familias sino que también se pudo evidenciar cómo afecta a las enfermeras la experiencia de cuidado de estas familias y sus hijos. CONCLUSIÓN: La enfermedad oncológica infantil provoca una situación de impacto emocional en las familias que se experimenta en todas las esferas de la vida. Contrariamente a la presunción adoptada en la premisa de investigación, las enfermeras perciben todas las vivencias descritas por las familias sobre el impacto de la enfermedad oncología infantil. Asimismo, fruto del cuidado humanizado y la relación terapéutica, las enfermeras muestran indicios de desgaste emocional que puede dificultar el cuidado., [eng] INTRODUCTION: Living the experience of having a child with cancer is a situation that creates a family crisis that affects not only structurally but also emotional. Nurses are professionals, who together with the multidisciplinary team, interact with these families, so it is of interest to know how to show this experience and its impact on families. For this to be able to improve health care practice that should include a holistic orientation with in the highly complex care that requires a child cancer. AIMS/OBJECTIVES: The main objective was to understand and analyze in profundity the experience at the time of diagnosis of childhood oncological disease in families and the perception of the phenomenon in nurses. The specific objectives were to analyze the impact on families of the debut of childhood cancer disease, to explore the perception of nurses about the impact and the experience of families in the onset of childhood cancer, and to compare the perception that families have with the perception of nurses regarding the onset of childhood cancer. METHODOLOGY: Qualitative study following an approach based on the hermeneutical phenomenology of Heidegger whose field of study were the Oncology and Day Hospital units of the Sant Joan de Deu Hospital in Barcelona. The informants were the families of children with cancer and the nurses dedicated to their care. In the selection of these informants the theoretical or intentional sampling technique was used, taking into account sociodemographic variables that helped to define the profile of the informant in both study groups. Until getting the theoretical saturation of the information. This saturation was achieved before ending the process of gathering information as it was interesting to be able to have the vision of the different informant profiles of each group. For the data collection, the semi-structured interview was used following a previously prepared topic script and the field diary. The type of analysis used was thematic under the content analysis method, following the QUAGOL (Qualitative Analysis Guide of Leuven) analysis method. The Nvivo10 program is used as a computer tool. As the analysis was a circular and continuous process, as we went deeper into the information received, we changed or added categories and subcategories. RESULTS: The interviews carried out were 14 in group 1 (families) and 17 in group 2 (nurses). In group 1 (families) 1060 units of meaning were obtained and grouped into 11 categories and 9 subcategories. In group 2 (nurses), 822 units of meaning were obtained, grouped into 12 categories and 7 subcategories. In group 1 (families), it was observed that the category that obtained the highest number of references in units of meaning was the repercussion of the disease in the family (REPERENFER) (n = 121) and, the least, it was taken care of sick child (CUIDADOHIJO) (n = 10) that referred to who was focused on caring for the child with cancer. In group 2 (nurses), it was observed that the category that obtained the highest number of references in meaning units was observed emotions (EMOENFER) (n = 134) and the least, presence of compassion fatigue (FATIGAENFERMERA) (n = 1). The results of this study describe the impact and experience of families before the oncological onset of their children. They show that it is a difficult experience to live and that affects all levels (economic, organizational, emotional, social) altering family processes. Also, there is an emotional impact that makes it impossible to process the situation they are living, given that the first feeling They feel it is pain and fear of the information they receive about the diagnosis of cancer. Many times the reactions experienced are anger, anger, denial, emotional block, guilt, sadness. The results also allowed us to detect that the nurses not only explained how they perceive the impact of the oncological disease onset in the families, but also how the nurses experience the care of these families and their children. CONCLUSIONS: Childhood oncology sickness causes a situation of emotional impact in families that is experienced in all spheres of life. Contrary to the presumption adopted in the research premise, the nurses perceive all the experiences described by the families about the impact of the childhood oncology disease. Likewise, as a result of humanized care and the therapeutic relationship, nurses evince signs of emotional exhaustion that can make care difficult.

[cat] ANTECEDENTS: els inhibidors d’histona deacetilasa (HDACi) han emergit els últims anys com potencials tractaments dirigits, amb la finalitat de revertir els canvis epigenètics associats a diferents tipus de càncer, incloent les neoplàsies hematològiques. La falta d’especificitat dels HDACi, però, dificulta la predicció dels seus efectes biològics i provoca una toxicitat no menyspreable, el que ha limitat el seu ús en la pràctica clínica. L’expressió de les HDACs no ha estat estudiada en les leucèmies agudes pediàtriques més que de manera parcial i en sèries amb un limitat número de pacients; per tant, són necessaris estudis que ajudin a aclarir el paper de cadascuna de les HDACs com a possibles biomarcadors i com a dianes terapèutiques, de cara a dirigir el tractament específic i personalitzat amb HDACi. HIPÒTESI: en aquest context, l’estudi global del perfil transcripcional de les HDACs en una sèrie àmplia i representativa de pacients pediàtrics amb diferents subtipus de leucèmia aguda permetria definir millor el seu impacte pronòstic i definir el seu rol com a dianes terapèutiques, ajudant a dirigir el tractament específic amb HDACi de forma més racional i individualitzada. OBJECTIUS: estudiar de forma global el perfil d’expressió de les HDAC1-11, SIRT1, SIRT7 i d’altres gens co-reguladors, MEF2C i MEF2D, en una sèrie de pacients pediàtrics amb leucèmia aguda diagnosticats i tractats en un sol centre. METODOLOGIA: anàlisi de l’expressió de l’mRNA de les HDAC1-11, SIRT1, SIRT7, MEF2C i MEF2D mitjançant PCR quantitativa en 211 pacients pediàtrics (0-18 anys), diagnosticats de leucèmia de novo des de l’any 2003 al 2017 en el nostre centre. Els pacients es van tractar uniformement d’acord als protocols consecutius de la Sociedad Española de Hematología y Oncología Pediátrica (SEHOP). Es va emprar un pool de pacients no-neoplàsics com a calibrador i també es va analitzar l’expressió dels diferents gens en cèl·lules CD34+ normals de moll d’os i a cèl·lules B CD19+ madures i limfòcits T madurs de sang perifèrica. RESULTATS: l’expressió de les HDACs va diferir en els diferents subtipus de cèl·lules hematopoètiques normals d’acord amb el grau de maduració i el llinatge. En els pacients amb leucèmia es va observar, en general, una sobreexpressió de les HDACs, amb perfils específics que correlacionaven amb característiques clíniques i biològiques i, fins i tot en algunes ocasions, amb la supervivència dels pacients. Així, alguns perfils d’expressió d’HDAC i el perfil de MEF2C semblaven reflectir, probablement, el llinatge i la maduresa dels blasts, mentre que d’altres identificaven la via oncogènica activa en les cèl·lules leucèmiques. Concretament, es va identificar un perfil d’expressió distintiu pels pacients amb reordenament del gen KMT2A (MLL), amb nivells elevats d’HDAC9 i MEF2D, independentment de l’edat, el partner del gen de fusió i el llinatge. A més, es va observar en els pacients amb LLA-B un pronòstic advers de la sobreexpressió de l’HDAC9, independentment de l’estat del gen KMT2A. CONCLUSIONS: en aquest treball s’han observat diferents perfils d’expressió segons els diferents subtipus de leucèmia aguda pediàtrica. Concretament, s’ha identificat un perfil distintiu dels pacients amb reordenament del gen KMT2A, amb la sobreexpressió de l’ HDAC9 i MEF2D, independentment del llinatge, de l’edat i del partner del gen de fusió. Aquests resultats aporten una imatge global de l’expressió de les HDACs en els pacients pediàtrics amb leucèmia aguda i recolzen el tractament dirigit amb HDACi més específics en seleccionats grups de pacients d’alt risc, com els pacients amb reordenament del gen KMT2A., [eng] Histone deacetylase inhibitors (HDACi) emerged as promising drugs in leukaemia, but their toxicity due to lack of specificity limited their use. Therefore, there is a need to elucidate the role of HDACs in specific settings. The study of HDAC expression in childhood leukaemia could help to choose more specific HDACi for selected candidates in a personalized approach. We analysed HDAC1-11, SIRT1, SIRT7, MEF2C and MEF2D mRNA expression in 211 paediatric patients diagnosed with acute leukaemia. We found a global overexpression of HDACs, while specific HDACs correlated with clinical and biological features, and some even predicted outcome. Thus, some HDAC and MEF2C profiles probably reflected the lineage and the maturation of the blasts and some profiles pointed out specific oncogenic pathways active in the leukaemic cells. Specifically, we identified a distinctive signature for patients with MLL rearrangement, with high HDAC9 and MEF2D expression, regardless of age, MLL-partner and lineage. Moreover, we observed an adverse prognostic value of overexpression of HDAC9, regardless of MLL rearrangement. Our results provide useful knowledge on the complex picture of HDACs expression in childhood leukaemia and support the directed use of specific HDACi to selected paediatric patients with acute leukaemia.

Introducción: vivir la experiencia de tener un hijo con cáncer es una situación que genera una crisis en la familia que afecta no solo a nivel estructural, sino también emocional. Las enfermeras son las profesionales miembros del equipo multidisciplinar que se relacionan más tiempo con estas familias, por lo que es interesante saber cómo evidencian esta experiencia para poder mejorar la práctica asistencial, que debe contemplar una orientación holística dentro de los cuidados de alta complejidad que precisa un niño oncológico. Objetivos: analizar el impacto en las familias producido por el debut de una enfermedad oncológica infantil; describir la percepción de las enfermeras sobre el impacto y la vivencia de las familias en el inicio de una enfermedad oncológica infantil y comparar la percepción que tienen las familias con la percepción de las enfermeras con respecto al debut de la enfermedad oncológica infantil. Ámbito de estudio: Unidad de Oncología y Hospital de Día del Hospital Sant Joan de Déu de Barcelona. Metodología: estudio cualitativo siguiendo un enfoque basado en la fenomenología hermenéutica de Heidegger. Los participantes serán las familias de niños con cáncer y las enfermeras dedicadas a su cuidado. Para la recogida de datos se utilizará la entrevista en profundidad y, si se considerara pertinente, el grupo de discusión. El tipo de análisis utilizado será el de la temática bajo el método de análisis del contenido, siguiendo el método de análisis Guía QUAGOL (Qualitative Analysis Guide of Leuven).

Organized and hosted by the Children's Tumor Foundation (CTF), the Neurofibromatosis (NF) conference is the premier annual gathering for clinicians and researchers interested in neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2), and schwannomatosis (SWN). The 2016 edition constituted a blend of clinical and basic aspects of NF research that helped in clarifying different advances in the field. The incorporation of next generation sequencing is changing the way genetic diagnostics is performed for NF and related disorders, providing solutions to problems like genetic heterogeneity, overlapping clinical manifestations, or the presence of mosaicism. The transformation from plexiform neurofibroma (PNF) to malignant peripheral nerve sheath tumor (MPNST) is being clarified, along with new management and treatments for benign and premalignant tumors. Promising new cellular and in vivo models for understanding the musculoskeletal abnormalities in NF1, the development of NF2 or SWN associated schwannomas, and clarifying the cells that give rise to NF1-associated optic pathway glioma were presented. The interaction of neurofibromin and SPRED1 was described comprehensively, providing functional insight that will help in the interpretation of pathogenicity of certain missense variants identified in NF1 and Legius syndrome patients. Novel promising imaging techniques are being developed, as well as new integrative and holistic management models for patients that take into account psychological, social, and biological factors. Importantly, new therapeutic approaches for schwannomas, meningiomas, ependymomas, PNF, and MPNST are being pursued. This report highlights the major advances that were presented at the 2016 CTF NF conference.

[spa] Evidencias recientes han mostrado que los tumores sólidos pediátricos, incluidos el neuroblastoma y el meduloblastoma, albergan una baja cantidad de mutaciones genéticas recurrentes, pero presentan una proporción significativa de alteraciones recurrentes en los mecanismos epigenéticos. Además, la epigenética es un mecanismo regulatorio fundamental durante el desarrollo en mamíferos. En este proyecto hemos estudiado los cambios epigenéticos que afectan a dos tumores neuronales pediátricos prototípicos, el neuroblastoma y meduloblastoma. Mediante el estudio de los cambios de metilación del ADN, los miRNA y la expresión génica, hemos identificado modificaciones genéticas y epigenéticas que subyacen a la base molecular de la patogénesis y tienen implicación clínica en la evolución de estos tumores neurales. El objetivo principal de nuestro proyecto era identificar marcadores moleculares y posibles dianas de interés para el desarrollo de nuevas estrategias terapéuticas. Este proyecto fue el primer estudio completo de metilación del ADN en neuroblastoma empleando microarrays de alta densidad. Detectamos por primera vez en neuroblastoma la presencia de metilación del ADN en citosinas no-CpG, asociada a tumores de bajo riesgo clínico. El estado de metilación detectado en el contexto no-CpG indica un papel potencial de esta metilación en la diferenciación y regulación transcripcional de genes clave el en desarrollo, como por ejemplo ALK. Observamos que la metilación del ADN en el neuroblastoma afecta no sólo a los promotores, sino también a las regiones intragénicas e intergénicas tanto en sitios CpG como no-CpG en dominios funcionales de la cromatina de genes implicados en desarrollo y cáncer. Los cambios de metilación del ADN en sitos CpG y no-CpG tanto dentro como fuera de islas CpG (CGI) y localizados en el cuerpo del gen podian estar asociados con el comportamiento clínico del neuroblastoma. Detectamos cambios en contexto no-CpG que sugieren que el neuroblastoma puede ser epigenéticamente diferente a lo largo de la terapia. Además, analizando citosinas fuera de las regiones promotoras, en el cuerpo del gen y de las regiones intergénicas, en sitios CpG asociados a CGI y en sitios no-CpG dentro y fuera de CGIs observamos una asociación de la metilación con el comportamiento clínico en neuroblastoma. La segunda parte del proyecto se centró en tratar de dar respuesta a la creciente necesidad de aplicar en la práctica clínica el sistema de clasificación del meduloblastoma en los subgrupos moleculares WNT, SHH, Grupo 3 y Grupo 4, recientemente identificados y propuestos mediante análisis (epi)genómicos. El reconocimiento de los subgrupos consenso ha cambiado la forma en que se estudia el meduloblastoma en el contexto de la investigación y cómo se diagnostica y trata en el contexto clínico. Estos subgrupos moleculares se definen actualmente mediante robustos sistemas de clasificación basados técnicas difícilmente incorporables a la rutina clínica de la mayoría de hospitales que tratan tumores cerebrales infantiles. Hemos desarrollado una metodología clínicamente aplicable, robusta, rápida y reproducible para la predicción exacta de subgrupos de meduloblastoma de muestras individuales en base a dos paneles compuestos por conjuntos reducidos de biomarcadores epigenéticos, y por tanto, potencialmente incorporables en la rutina de diagnóstico. Los biomarcadores epigenéticos identificados podían aplicarse a muestras individuales de ADN de meduloblastoma obtenidas a partir de tejido congelado o FFPE. El patrón bimodal de los paneles permitía el análisis mediante diversas técnicas moleculares, tanto cuantitativas como cualitativas. Nuestro enfoque era técnicamente más simple, rápido y coste efectivo en comparación con las actuales técnicas estándar de clasificación de subgrupos de meduloblastoma., [eng] Recent evidence has shown that pediatric solid tumors harbor a paucity of recurrent genetic mutations as compared to other tumors from adults, suggesting that additional mechanisms such as epigenetic alterations may play an important role in the molecular pathogenesis of developmental tumors. So far the great majority of studies that have investigated DNA methylation in developmental tumors were biased towards CpG sites and promoter regions. Recent genome- wide studies are starting to reveal a role for DNA methylation outside such genomic contexts. Furthermore, it has recently been described that cytosine methylation also occurs in sites other than CpG dinucleotides (mCHG and mCHH) in embryonic stem cells and during brain development. However, DNA methylation at non-CpG contexts has rarely been described in cancer. We have analyzed the DNA methylome of two prototypical developmental neural tumors, neuroblastoma and medulloblastoma, using high-density microarrays with the aim of detecting epigenetic modifications at a genome-wide level that may have clinical relevance in the pathogenesis of these pediatric tumors, to identify molecular markers and potential targets of interest for the development of new therapeutic strategies. Our DNA methylation studies in neuroblastoma using high-density microarrays have defined the epigenetic landscape of this pediatric tumor and its potential clinicopathological impact. Our results reveal that: - DNA methylation changes in neuroblastoma affect not only promoters but also intragenic and intergenic regions at CpG sites and, for the first time in neuroblastoma, at non-CpG sites. - These epigenetic changes show a non-random distribution relative to functional chromatin states, and frequently target development and cancer-related genes relevant for neuroblastoma, such as CCND1 and ALK. - DNA methylation patterns in non-CpG sites provide new insights into the differentiation stage of high and low-risk neuroblastomas. - DNA methylation changes at CpG and non-CpG sites are strongly associated with clinicopathological features of neuroblastoma and with patient outcome. Furthermore, we have developed a simplified and reproducible approach to classify medulloblastoma tumors into clinically relevant subgroups applying epigenetic markers. Using this strategy, MB patients can be accurately classified into the three consensus subgroups WNT, SHH and non-WNT/non-SHH. In addition, we propose a similar approach for the specific classification of Group 3 and Group 4 medulloblastoma tumors. The proposed strategies allows for classification of single DNA samples from biopsies both frozen as well as FFPE of primary, metastasis or relapse compartments, using diverse molecular approaches. Our results show that the proposed strategy is robust, accurate, and cost-effective, making it adequate for molecular subgrouping of medulloblastoma in daily diagnostic practice of most centers treating children with brain tumors.

INTRODUCCIÓN: Se considera a Ferguson (1861) el primer comunicante de una resección de rodilla, Verneuil (1863) el autor de la primera artroplastia de interposición y Gluck (1890) responsable de las primeras artroplastias protésicas. Los sarcomas óseos primarios en niños y adolescentes se localizan habitualmente alrededor de la rodilla, existiendo diferentes modelos comercializados de megaprótesis tumorales para pacientes jóvenes o niños esqueléticamente inmaduros. Los análisis de elementos finitos han sido progresivamente incorporados en el campo de la cirugía ortopédica y traumatología para el estudio de implantes de diversas formas y solicitaciones mecánicas. HIPÓTESIS DE TRABAJO: La diferente colocación del implante protésico endomedular y la posición de la rodilla, alteran la distribución de tensiones en el conjunto hueso-prótesis. OBJETIVOS DE LA TESIS: 1.- Realizar un modelo informático de prótesis total de rodilla con vástagos endomedulares largos dotada de constricción y estudiarla mediante un análisis de elementos finitos. 2.- Localizar las zonas de la prótesis total de rodilla y del hueso receptor donde se acumulan mayores tensiones. 3.- Demostrar que el centrado del vástago protésico en el canal medular modifica la transmisión de esfuerzos en el conjunto articular. 4.- Valorar si el grado de flexión de la rodilla modifica las tensiones sobre el conjunto Hueso-prótesis total de rodilla. 5.- Realizar una valoración clínica en pacientes menores de dieciocho años del comportamiento de las prótesis totales de rodilla tumorales. RESULTADOS: Estudio experimental: Los materiales más rígidos (metal) soportan una mayor tensión y los materiales más elásticos (plástico) presentan unas mayores deformaciones. El mayor nivel de tensión se produce en el extremo de la prótesis. Las magnitudes máximas de las deformidades que se producen en todas las piezas son similares, independientemente de si la prótesis está centrada, variando las tensiones en la parte metálica de la prótesis. Estudio clínico: Se han estudiado 14 casos de pacientes menores de 18 años portadores de artroplastia tumoral de rodilla. Patología: Osteosarcoma 12; Sarcoma de Ewing: 2 Afectación tumoral femoral/tibial: 8/6 Se han valorado los parámetros clínicos de dolor; arco de movilidad; marcha; utilización de escaleras y grado de satisfacción. CONCLUSIONES: 1.- Se ha obtenido un modelo informático de prótesis total de rodilla dotada de constricción, de vástagos endomedulares largos y ha sido estudiado mediante un sistema de análisis por elementos finitos. 2.- Del conjunto de materiales que componen la articulación protésica, aquellos que son más rígidos (materiales metálicos) soportan una mayor tensión, mientras que los más elásticos (materiales plásticos) presentan una mayor variación de deformaciones que alivian los esfuerzos recibidos. 3.- La parte crítica de la estructura hueso-prótesis es la sección en la que finaliza el vástago de la prótesis, ya que en ella se produce una fuerte variación en la rigidez, lo que conlleva un mayor nivel de tensiones. 4.- Las magnitudes máximas de las deformaciones que se producen en todas las piezas, independientemente que se encuentre la prótesis centrada o no, son similares, aunque sus distribuciones varían. 5.- En los materiales plásticos y en el fémur, no se aprecia una variación importante de tensiones por la diferente posición de la prótesis. Sin embargo, en la parte metálica de la prótesis descentrada sí que existen aumentos considerables de tensión. 6.- Las tensiones en el conjunto aumentan con el grado de flexión tanto si los vástagos protésicos están centrados como si no lo están. 7.- Los parámetros clínicos de dolor, arco de movilidad de la rodilla, marcha, utilización de escaleras y grado de satisfacción han presentado unos buenos resultados en la mayoría de los casos de artroplastias tumorales de rodilla en pacientes menores de dieciocho años al año de la intervención quirúrgica., Introduction Primary bone sarcomas in children and adolescents are usually located around the knee. Different models of megaprosthesis are available for the treatment of young patients. Finite element analysis has been used to study implants in orthopedic surgery and traumatology. Hypothesis The different positioning of the intramedullary stem and the prosthetic knee position, modifies the stress distribution. Material and Methods experimental study: An finite element analysis of a knee prosthesis in different position has been made. clinical study: We have studied 14 cases of patients under 18 years of age with knee megaprosthesis after knee tumor resection.(Osteosarcoma 12 patients; Ewing Sarcoma 2 patients). Conclusions 1. A computer model of constricted total knee prosthesis with long intramedullary stems has been obtained and studied by a finite element analysis. 2. The more rigid materials (metallic materials) support greater tension, while the more elastic (plastics) have a greater variation of strain. 3. The critical part of the bone-prosthesis structure is located at the end of the prosthesis stem. 4. Tensions increase with the degree of knee flexion in all models. 5. The clinical parameters of pain, range of knee motion, walking distance, use of stairs and satisfaction have shown good results in most cases of knee replacements in patients under eighteen year of age.

[eng] A new combined microdialysis – tumor homogenate method for the determination of compartmental (vascular, extra- and intracellular) SN-38 distribution in patient-derived xenografts (PDX) generated from pediatric solid tumors from fresh tumor samples from patients of Sant Joan de Deu Barcelona Hospital was developed. SN-38 in late-stage (chemoresistant) tumors presented limited distribution into the intracellular compartment while drug distribution into this compartment was significantly higher in early-stage (sensitive) models when SN-38 was administered as its prodrug irinotecan. Furthermore, two polymeric drug delivery systems were developed for the local and systemic administration of SN-38. Poly(lactic) acid electrospun nanofiber matrices with microcrystals of SN-38 were developed for the local administration of SN-38. Matrices showed maintained release of SN-38 over 48 h with local distribution and efficacy delaying tumor growth over PDX models. Dialysates showed limited SN-38 diffusion from the matrices through the tumor tissue, suggesting this therapy could only be useful for the local tumor control after successful surgery of the tumor or where only microscopic tumor seeds are left. Systemic administration of SN-38 was possible by encapsulating the drug into poly(lactic-co-glycolic) acid with polyethylene glycol nanoparticles, which were decorated with 3F8 monoclonal antibody, an anti-GD2 antibody that recognizes the ganglioside GD2 overexpressed on the surface of neuroblastoma cells surface for active targeting. Nanoparticles released SN-38 over 2 days and tumor exposition to SN-38 was increased when compared with the administration of an equimolar dose of irinotecan, and that was correlated with improved efficacy over the conventional irinotecan where 10 administrations of the drug had reduced efficacy compared to the direct administration of SN-38 in the targeted nanoparticles. Both nanofiber matrices and nanoparticles showed to be good platforms for SN-38 administration reducing systemic exposition by localizing SN-38 at the tumor microenvironment and significantly delaying tumor growth as shown in the efficacy studies. Thus, polymeric local drug delivery systems strategy should be of high interest for the potential future treatment of chemoresistant tumors

Renal malignancies are common in children. While the majority of malignant renal masses are secondary to Wilms tumor, it can be challenging to distinguish from more aggressive renal masses. For suspicious renal lesions, it is crucial to ensure prompt diagnosis in order to select the appropriate surgical procedure and treatment. This review article will discuss the common differential diagnosis that can be encountered when evaluating a suspicious renal mass in the pediatric population. This includes clear cell sarcoma of the kidney, malignant rhabdoid tumor, renal medullary carcinoma and lymphoma. Copyright: The Authors.

A presente tese tem como objetivo compreender o desempenho educacional de crianças com câncer de 6 a 12 anos de idade matriculadas nos anos iniciais do ensino fundamental, investigando como são desenvolvidas as práticas pedagógicas nos ambientes hospitalares. Um estudo de caso embasou esta pesquisa, a partir de uma relação sócio-histórica. Foram analisadas as narrativas de 10 sujeitos, fazendo-o com profundidade, segundo as interfaces das narrativas das crianças com câncer e seus responsáveis. Ter uma doença na infância acomete um momento relevante na vida, que é o período em que se está descobrindo o mundo, um período em que, em consequência do rápido desenvolvimento do sistema nervoso, é fundamental que ocorra uma ampla e adequada variação dos estímulos ambientais, favorecendo assim o desenvolvimento biopsicossocial. As narrativas das crianças escolhidas como sujeitos da pesquisa desvelaram significados da inclusão escolar no hospital para as suas vidas, o que nos permitiu refletir acerca das contribuições do acompanhamento pedagógico como elemento de continuidade da escolarização propulsora de aprendizagens e socialização. Com base nos relatos e nas observações apresentadas, podemos perceber que a aprendizagem se faz presente nas experiências infantis. Assim, portanto, é preciso atribuir à voz da criança, ao seu pensar, ao seu querer, a suas dores a importante capacidade dela transformar e revelar os seus caminhos na saúde e na educação, de forma a favorecer os processos de ensino-aprendizagem pressupondo as necessidades, os desejos e as inquietações próprias da infância. ABSTRACT- This thesis aims to understand the child’s educational performance with cancer between 6 to 12 years old matriculate in the early years of elementary school, investigating how are developed the pedagogical practice in the hospital environment providing opportunities to learning of these children. One case study based this research from a social-historical relationship. The narratives of 10 subjects were analyzed with depth, according to the interfaces of children’s narratives with cancer and their caregivers. Having a disease in childhood affects an important time in a life, the moment which it is discovering the world, a period that due to of the rapid development of the nervous system, it is fundamental that occur a wide and appropriate variation of environmental stimuli, thus favoring the biopsychosocial development. The children’s narratives, the research subject, unveiled meanings of school inclusion in the hospital for their lives, allowing us to reflect about the contributions of educational support, as part of continuing driving school learning and socialization. Based on the presented reports and observations, we can realize that learning, is present in children's experiences. Therefore, assign voice to the child, to his thinking, his will, his pain, as an appeal to transform and reveal the ways of health and education, which might favor the processes of teaching and learning, presuppose the needs, the desires and his own anxieties of childhood.

Treballs Finals de Grau d'Educació Social, Facultat d'Educació, Universitat de Barcelona, Curs: 2014-2015, Tutor: Jordi Méndez, Esta investigación pretende conocer la importancia de las buenas prácticas socioeducativas que puede aportar el educador social en el ámbito hospitalario, centrándome concretamente en la oncología pediátrica, debido a que es un campo emergente para la educación social. Por otro lado, también pretende elaborar algunas propuestas de mejora en la formación de los voluntarios de AFANOC (Associació de Familiars i Amics de Nens Oncològics de Catalunya). Como principal conclusión, se ha extraído que el educador social puede ser muy competente en el ámbito de la oncología pediátrica y puede realizar diferentes funciones que requieren de su presencia para mejorar la atención socioeducativa a los niños y sus familias. Por otro lado, también se ha podido ver que en la formación de los voluntarios es muy importante la formación continuada y obligatoria para todos los voluntarios de la entidad y las reuniones quincenales para compartir la experiencia y algunas dudas, especialmente los voluntarios del hospital, ya que es una situación más compleja.

El sarcoma de Ewing (SE) es el segundo tumor óseo maligno infantil más frecuente y presenta una alta incidencia de enfermedad metastásica. Este tipo de tumores presentan una translocación génica característica que da origen a una proteína de fusión, normalmente EWS/FLI1. Esta proteína de fusión actúa como factor de transcripción aberrante, regulando la expresión de diferentes genes implicados en la iniciación, mantenimiento y progresión del tumor. Nuestro grupo describió como uno de estos genes diana a caveolina 1 (CAV1), describiendo además su papel determinante en el fenotipo maligno del SE, en la tumorigénesis, en la angiogénesis y en la resistencia a apoptosis inducida por quimioterapia. Para investigar el papel concreto de CAV1 en el proceso metastásico de este sarcoma, se creó un modelo de baja expresión de CAV1 en líneas celulares de SE y se determinaron cambios en su capacidad migratoria, invasiva y metastásica. En los ensayos in vitro se halló una menor capacidad migratoria de las células con silenciamiento de CAV1 y una reducción en la expresión de metaloproteinasa 9 (MMP-9) y en la actividad de MMP-2, ambas MMPs implicadas en el proceso de invasión. La regulación de la actividad de MMP-2 parece estar relacionada con la posible regulación que ejerce CAV1 en la función de la MMP de membrana tipo 1 (MT1-MMP), proteína fundamental para la activación de MMP-2. Por otro lado, en este estudio se propone que CAV1 promueve la expresión de MMP-9 transcripcionalmente a través de la regulación de la activación de la vía de señalización de ERK1/2 (Extracellular signal-regulated kinase 1/2). En nuestro modelo, ERK1/2 activo translocaría al núcleo donde activaría los factores de transcripción responsables de la activación del promotor de MMP-9. Por otro lado, la fosforilación de RSK2 (Ribosomal S6 kinase 2) por parte de ERK1/2 en el citoplasma, produciría la activación de RSK2 que a su vez activaría la proteína ribosomal rpS6, uno de los responsables de la iniciación de la traducción, por lo que también podría estar influyendo a la producción de MMP-9 a este nivel. Según nuestros resultados, CAV1 estaría influyendo en la capacidad migratoria de las células de SE mediante dos mecanismos: 1) a través de la activación de la vía de ERK1/2 y 2) mediante la unión a diferentes proteínas con dominio SH2 a través de la fosforilación de CAV1 en la tirosina 14. ERK1/2 influye en la regulación de la capacidad migratoria de una forma de pendiente o independiente de RSK1. Además, en los ensayos de metástasis experimental in vivo las células con inhibición de CAV1 presentaron una menor incidencia de metástasis pulmonar, hecho que correlacionó con una disminución en la expresión de SPARC (Secreted protein acidic and rich in cysteine), una proteína de adhesión importante en procesos metastásicos. En resumen, nuestros resultados evidencian la importancia de CAV1 en el proceso metastásico del SE., Ewing’s sarcoma (ES) is the second most common bone tumor in childhood and occurs with a high incidence of metastatic disease. Such tumors have a characteristic gene translocation that gives rise to a fusion protein, most commonly EWS/FLI1. This fusion protein acts as an aberrant transcription factor regulating the expression of different target genes involved in the initiation, maintenance and progression of the tumor. Our group described caveolin 1 (CAV1) as one of these target genes, describing its role in the malignant phenotype, tumorigenicity and resistance to chemotherapy-induced apoptosis of ES cell lines. To investigate the specific role of CAV1 in the metastatic process of this sarcoma, we established a model of low expression of CAV1 in cell lines of ES. Then, we measured changes in their migratory capacity, invasiveness and metastatic potential. In vitro, we found a lower migratory capability of CAV1 knockdown cells and a reduction in MMP-9 expression and MMP-2 activity. The regulation of MMP-2 activity seems to be related to the possible regulation that CAV1 exerts on the function of MT1- MMP, an essential protein for the activation of MMP-2. On the other hand, we suggest that CAV1 promotes the expression of MMP-9, both transcriptionaly and post-transcriptionaly, through regulating ERK1/2 signaling pathway. In our model, activated ERK1/2 would translocate to the nucleus where it would activate the transcription factors responsible for MMP-9 promoter activation. At the cytoplasm, activated ERK1/2 would phosphorylate and activate RSK2, which, in turn, would promote rpS6 activation, leading to protein translation initiation. Our results indicate that CAV1 is regulating migratory capability of ES cells by two different mechanisms; 1) through ERK1/2 pathway activation, 2) by linking several proteins bearing SH2 domains trough phosphorylated Tyr14 of CAV1. ERK1/2 seems to regulate cell migration in both RSK1-dependent and independent manner. In addition, experimental metastasis assays in vivo showed that, CAV1 knockdown cells had a lower incidence of pulmonary metastasis, a fact that correlated with a decrease in the expression of SPARC, a major adhesion protein in metastatic processes. In summary, our results demonstrate the importance of CAV1 in the metastatic process on ES tumors.

Tesi realitzada al Laboratori de Tumors del Desenvolupament, Hospital-Fundació Sant Joan de Déu, [spa] El neuroblastoma (NB) agrupa un espectro muy heterogéneo de tumores que evolucionan de forma radicalmente distinta. La variedad de comportamiento clínico del NB determina el enfoque terapéutico, que puede variar entre un abordaje terapéutico intensivo multimodal o una actitud expectante. Por lo tanto, la clasificación precisa de los diferentes subtipos de NB es importante para determinar el tratamiento más apropiado. Actualmente los sistemas de clasificación de riesgo clínico en NB se basan en distintos parámetros clínicos, biológicos y morfológicos. No obstante, todavía existen casos donde estos sistemas de clasificación muestran una utilidad clínica limitada. Existen perfiles de expresión génica que definen el comportamiento biológico de cada subgrupo de NB y que permiten predecir el pronóstico de los pacientes. Sin embargo, las listas de genes son demasiado extensas para poder implementarlas en la rutina clínica. En esta tesis, hemos desarrollado un modelo estadístico de predicción de pronóstico basado en la combinación lineal de los niveles de expresión de tres genes, CHD5, NME1 y PAFAH1B1, diferencialmente expresados en subgrupos de NB con comportamiento clínico distinto y asociados de forma estadísticamente significativa con la evolución clínica del paciente. Su potencial predictivo ha sido validado utilizando datos de expresión obtenidos experimentalmente mediante qRT-PCR y de dos bases de datos públicas de microarrays de expresión. En todas las cohortes analizadas el modelo muestra una excelente capacidad para clasificar a los pacientes con una evolución clínica distinta. Los distintos análisis multivariantes ha identificado el modelo como un marcador de predicción de pronóstico independiente a los marcadores actualmente aceptados para NB. En conclusión, se ha desarrollado un modelo estadístico de predicción de pronóstico basado en una técnica convencional (qRT-PCR), que podría ayudar a refinar los actuales sistemas de estratificación de riesgo clínico en NB. Uno de los genes incluidos en este modelo, CHD5, es un potencial gen supresor de tumores localizado en la región cromosómica 1p36.31, recurrentemente perdida en NB. Estudios previos han identificado que CHD5 se expresa en tejidos neurales normales y en NB de bajo riesgo clínico. Nosotros hemos descrito por primera vez el perfil inmunofenotípico de CHD5. En tejidos neurales normales se identificó expresión nuclear en células de estirpe neuronal mientras que las células gliales mostraron ausencia de tinción. La caracterización en los tumores neuroblásticos (TN) ha identificado la expresión proteica circunscrita al núcleo de las células neuroblásticas en diferenciación y de las células ganglionares, y ausente en los neuroblastos indiferenciados y las células de tipo Schawnn. En los TN, la tinción nuclear muestra una correlación estadísticamente significativa con una evolución clínica más favorable de los pacientes. Sugiriendo que la tinción inmunohistoquímica de CHD5 podría representar un marcador útil para refinar los actuales sistemas de determinación del pronóstico en NB. El análisis de la expresión de este gen en muestras apareadas de NB obtenidas al diagnóstico y post-tratamiento, también sugiere podría representar un marcador inmunohistoquímico clínicamente útil para una identificación rápida de pacientes que no se benefician del tratamiento convencional ya que actualmente en NB no existe ningún biomarcador de respuesta a tratamiento. Las modificaciones epigenéticas representan uno de los principales mecanismos de modulación de la expresión génica. Alteraciones en estos mecanismos, como la alteración del patrón de metilación del ADN, podrían estar implicadas en las variaciones de expresión génica identificadas entre subgrupos de NB. En NB se han identificado numerosos genes que sufren hipermetilación así como la asociación entre subgrupos clínicos de riesgo y genes hipermetilados. Sin embargo el patrón global de metilación del NB es aún considerablemente desconocido. Mediante microarrays hemos realizado un análisis global del estado de metilación del genoma del NB que nos ha permitido identificar patrones de metilación específicos del NB, así como patrones distintivos entre subgrupos clínicos y biológicos de NB. Nuestras observaciones muestran como el ADN del NB se ve afectado por una elevada disminución de los niveles de metilación. Dicha hipometilación es gen-específica y afecta a funciones biológicas relacionadas con cáncer así como a genes relevantes para la patogénesis del NB como CCND1. Cabe destacar que la metilación diferencial de CCND1 afecta principalmente a una región evolutivamente conservada y funcionalmente relevante localizada en 3’UTR, sugiriendo que la hipometilación fuera de las regiones promotoras puede tener un papel en el desarrollo del NB. La hipermetilación afecta genes involucrados en el desarrollo celular y en la proliferación, como RASSF1A, POU2F2 o HOXD3 entre otros. Los resultados obtenidos proporcionan nuevos candidatos a biomarcadores epigenéticos asociados al NB, así como nuevos conocimientos sobre las bases moleculares de estos tumores., [eng] Neuroblastoma (NB) is heterogeneous in terms of their biological, genetic and morphological characteristics and exhibit radically different outcomes. Since treatment strategies vary from a “watch and wait” approach to multimodal intensive regimens, precise risk assessment is critical for therapeutic decisions. Various combinations of prognostic markers have been used successfully for risk group distinction, yet there remain cases where these markers have demonstrated limited clinical utility. Microarray gene studies have contributed to identify set of genes with prognostic importance in NB. However, it use in clinical practice is limited by the large sets of genes identified. We developed a PCR-based predictor model using the expression patterns of three genes (CHD5, NME1 and PAFAH1B1) associated with NB patient’s outcome. The validation process showed that our model could stratify patients into groups with markedly divergent clinical outcome. Multivariate analysis corroborated that the proposed model was an independent predictor marker for survival on NB patients. In conclusion, we propose a robust and technically simple PCR-based one score predictor model, which could help refine current stratification systems of clinical risk stratification of NB. CHD5, one of the genes included on the predictor model, is a tumor suppressor gene located on chromosome 1p36.31, a region recurrently lost in high risk NB. Previous data showed a restricted gene expression to neuronal-derived tissues and in NB with low risk features. We have described for the first time the immunophenotypic profile of CHD5 in normal human neural tissues as well as primary neuroblastic tumors (NT). In TN, CHD5 immunoreactivity was found restricted to differentiating neuroblasts and absent in undifferentiated neuroblasts and stromal Schwann cells. A strong correlation of CHD5 expression with favorable clinical evolution was found. Our results suggest that CHD5 could represent an outcome marker in NB that can be tested by conventional immunohistochemistry. Disruption of DNA methylation is a hallmark of human cancer. Several genes have been described as hypermethylated in NB and have been related to NB clinical risk groups and patient outcome. However, genome-wide DNA methylation patterns have not been extensively studied. Differential microarray-based DNA methylation analyses, allowed us to identify patterns characteristic for NB so as NB clinical and biological subtypes. We observed that gene-specific loss of DNA methylation is more prevalent than gene promoter hypermethylation. Remarkably, such hypomethylation affected cancer-related biological functions and genes relevant to NB pathogenesis as CCND1. In particular, CCND1 differential methylation affects mostly an evolutionary conserved functionally relevant 3’-UTR region, suggesting that hypomethylation outside promoter regions may play a role in NB pathogenesis. Hypermethylation targeted genes involved in cell development and proliferation such as RASSF1A, POU2F2 or HOXD3, among others. Our results provide new epigenetic biomarkers candidate associated with NB as well as insights into the molecular pathogenesis of this tumor.

[spa] El sarcoma de Ewing (SE) es el segundo tumor óseo maligno infantil más frecuente y presenta una alta incidencia de enfermedad metastásica. Este tipo de tumores presentan una translocación génica característica que da origen a una proteína de fusión, normalmente EWS/FLI1. Esta proteína de fusión actúa como factor de transcripción aberrante, regulando la expresión de diferentes genes implicados en la iniciación, mantenimiento y progresión del tumor. Nuestro grupo describió como uno de estos genes diana a caveolina 1 (CAV1), describiendo además su papel determinante en el fenotipo maligno del SE, en la tumorigénesis, en la angiogénesis y en la resistencia a apoptosis inducida por quimioterapia. Para investigar el papel concreto de CAV1 en el proceso metastásico de este sarcoma, se creó un modelo de baja expresión de CAV1 en líneas celulares de SE y se determinaron cambios en su capacidad migratoria, invasiva y metastásica. En los ensayos in vitro se halló una menor capacidad migratoria de las células con silenciamiento de CAV1 y una reducción en la expresión de metaloproteinasa 9 (MMP-9) y en la actividad de MMP-2, ambas MMPs implicadas en el proceso de invasión. La regulación de la actividad de MMP-2 parece estar relacionada con la posible regulación que ejerce CAV1 en la función de la MMP de membrana tipo 1 (MT1-MMP), proteína fundamental para la activación de MMP-2. Por otro lado, en este estudio se propone que CAV1 promueve la expresión de MMP-9 transcripcionalmente a través de la regulación de la activación de la vía de señalización de ERK1/2 (Extracellular signal-regulated kinase 1/2). En nuestro modelo, ERK1/2 activo translocaría al núcleo donde activaría los factores de transcripción responsables de la activación del promotor de MMP-9. Por otro lado, la fosforilación de RSK2 (Ribosomal S6 kinase 2) por parte de ERK1/2 en el citoplasma, produciría la activación de RSK2 que a su vez activaría la proteína ribosomal rpS6, uno de los responsables de la iniciación de la traducción, por lo que también podría estar influyendo a la producción de MMP-9 a este nivel. Según nuestros resultados, CAV1 estaría influyendo en la capacidad migratoria de las células de SE mediante dos mecanismos: 1) a través de la activación de la vía de ERK1/2 y 2) mediante la unión a diferentes proteínas con dominio SH2 a través de la fosforilación de CAV1 en la tirosina 14. ERK1/2 influye en la regulación de la capacidad migratoria de una forma de pendiente o independiente de RSK1. Además, en los ensayos de metástasis experimental in vivo las células con inhibición de CAV1 presentaron una menor incidencia de metástasis pulmonar, hecho que correlacionó con una disminución en la expresión de SPARC (Secreted protein acidic and rich in cysteine), una proteína de adhesión importante en procesos metastásicos. En resumen, nuestros resultados evidencian la importancia de CAV1 en el proceso metastásico del SE., [eng] Ewing’s sarcoma (ES) is the second most common bone tumor in childhood and occurs with a high incidence of metastatic disease. Such tumors have a characteristic gene translocation that gives rise to a fusion protein, most commonly EWS/FLI1. This fusion protein acts as an aberrant transcription factor regulating the expression of different target genes involved in the initiation, maintenance and progression of the tumor. Our group described caveolin 1 (CAV1) as one of these target genes, describing its role in the malignant phenotype, tumorigenicity and resistance to chemotherapy-induced apoptosis of ES cell lines. To investigate the specific role of CAV1 in the metastatic process of this sarcoma, we established a model of low expression of CAV1 in cell lines of ES. Then, we measured changes in their migratory capacity, invasiveness and metastatic potential. In vitro, we found a lower migratory capability of CAV1 knockdown cells and a reduction in MMP-9 expression and MMP-2 activity. The regulation of MMP-2 activity seems to be related to the possible regulation that CAV1 exerts on the function of MT1- MMP, an essential protein for the activation of MMP-2. On the other hand, we suggest that CAV1 promotes the expression of MMP-9, both transcriptionaly and post-transcriptionaly, through regulating ERK1/2 signaling pathway. In our model, activated ERK1/2 would translocate to the nucleus where it would activate the transcription factors responsible for MMP-9 promoter activation. At the cytoplasm, activated ERK1/2 would phosphorylate and activate RSK2, which, in turn, would promote rpS6 activation, leading to protein translation initiation. Our results indicate that CAV1 is regulating migratory capability of ES cells by two different mechanisms; 1) through ERK1/2 pathway activation, 2) by linking several proteins bearing SH2 domains trough phosphorylated Tyr14 of CAV1. ERK1/2 seems to regulate cell migration in both RSK1-dependent and independent manner. In addition, experimental metastasis assays in vivo showed that, CAV1 knockdown cells had a lower incidence of pulmonary metastasis, a fact that correlated with a decrease in the expression of SPARC, a major adhesion protein in metastatic processes. In summary, our results demonstrate the importance of CAV1 in the metastatic process on ES tumors.

Bone and soft tissues tumours in children

The development of resistance to chemotherapeutic drugs is the main obstacle to the successful treatment of many cancers, including childhood neuroblastoma, the most common solid tumour of infants. One factor that may play a role in determining response of neuroblastoma tumours to therapeutic agents is the p53 tumour suppressor gene. A number of previous studies have suggested that this tumour suppressor protein is inactive in neuroblastoma due to its cytoplasmic sequestration. This thesis therefore has examined the functionality of p53 and its role in determining drug response of neuroblastoma cells. An initial study was undertaken that characterised an unusually broad multidrug resistance (MDR) phenotype of a neuroblastoma cell line (IMR/KAT100). The results demonstrated that the MDR phenotype of the IMR/KAT100 cells was associated with the acquisition of mutant p53. To explore the role of p53 in drug resistance further, p53-deficient variants in cell lines with wild-type p53 were generated by transduction of p53-suppressive constructs encoding either shRNA or a dominant-negative p53 mutant. Analysis of these cells indicated that: (i) in contrast to previous reports, wild-type p53 was fully functional in all neuroblastoma lines tested, as evidenced by its activation and nuclear translocation in response to DNA damage, transactivation of target genes and control of cell cycle checkpoints; (ii) inactivation of p53 in neuroblastoma cells resulted in establishment of an MDR phenotype; (iii) knockdown of mutant p53 did not revert the drug resistance phenotype, suggesting it is determined by loss of wild-type function rather than gain of mutant function; (iv) p53-dependent cell senescence, the primary response of S-type neuroblastoma cells to DNA damage, is replaced, after p53 inactivation, by mitotic catastrophe and subsequent apoptosis. In contrast to neuroblastoma, p53 suppression had no effect or increased drug susceptibility in several other tumour cell types, indicating the importance of tissue context for p53- mediated modulation of tumour cell sensitivity to treatment. Taken together, these data provide strong evidence for p53 having a role in mediating drug resistance in neuroblastoma and suggest that p53 status may be an important prognostic marker of treatment response in this disease.

Antecedentes y objetivos: La mayor supervivencia en el cáncer infantil condiciona una mayor preocupación por los efectos tardíos del cáncer y su tratamiento, que afectan a 2/3 partes de los supervivientes, destacando los endocrinológicos. Los objetivos generales son: 1) Ampliar el conocimiento de los efectos tardíos del tratamiento oncológico sobre la pubertad y la función gonadal de los supervivientes del cáncer infantil; 2) Definir marcadores de la función gonadal en niños en edades pre, intra y postpuberales.Pacientes y métodos: Se definieron un grupo de estudio y un grupo control. El primero incluía pacientes con antecedentes de cáncer infantil, que llevaran un periodo igual o menor de 2 años en remisión completa y sin tratamiento, con edad entre 7-18 años al iniciar el estudio. Se excluyeron los tratados exclusivamente con cirugía, los diagnosticados de tumores gonadales y aquéllos con diseminación gonadal de su neoplasia. Se seleccionaron 126 pacientes (72 niños y 54 niñas). El segundo incluyó niños sanos de 7 a 18 años (58 niños y 56 niñas). Se realizó una evaluación clínica, valorando curva de crecimiento, desarrollo puberal según Tanner, volumen testicular y ciclo menstrual. Los niños se clasificaron según su desarrollo puberal en: estadio I, II, III y IV-V. Se realizó una determinación de la concentración sérica basal de hormona folículo-estimulante (FSH), hormona luteinizante (LH), testosterona, estradiol e inhibina B. A los varones del grupo de estudio mayores de 15 años se les proponía un seminograma, y a las niñas puberales una ecografía pélvica. Análisis estadístico: se utilizó el paquete SPSS 12.0 (significación del 5%). Resultados: Grupo control: en varones la inhibina B aumentaba precozmente al inicio de la pubertad, y después se mantenía constante, mientras que FSH, LH y testosterona seguían aumentando, destacando una correlación negativa entre FSH e inhibina B a partir de la mitad de la pubertad. En las niñas las hormonas aumentaban durante el desarrollo con una correlación positiva entre ellas. Grupo de estudio: la media de edad al diagnóstico fue de 4,93 años, con una media de 6,53 años transcurridos desde el fin del tratamiento. Respecto al desarrollo puberal, un 6% de varones presentaba retraso puberal y un 15% de niñas pubertad adelantada o precoz. El seminograma se efectuó en 10 varones (2 con azoospermia, 2 con astenozoospermia y uno con aspermia). La ecografía pélvica fue normal en 35 de 38 niñas. Comparando el grupo de estudio versus el grupo control, los varones en estadio I y II tenían una edad significativamente superior. En el estadio II FSH, LH y testosterona fueron significativamente superiores, y en el estadio III se mantenían las diferencias para LH y testosterona. En las niñas no había diferencias en las variables de perfil, pero en el estadio I la inhibina B era significativamente inferior. Entre los varones, 19 (26,4%) presentaban insuficiencia tubular, asociada significativamente con la edad al inicio del tratamiento y con el trasplante de médula ósea (TMO), y 5 (7%) insuficiencia de las células de Leydig, asociada significativamente con la radioterapia y el TMO. Entre las niñas, 11 (20,4%) tenían insuficiencia ovárica parcial, asociada significativamente con la radioterapia, la quimioterapia gonadotóxica, el TMO y los tumores del sistema nervioso central.Conclusiones: La edad prepuberal al inicio del tratamiento no protege del daño gonadal. Todos los niños tratados de un cáncer deben ser vigilados cuidadosamente durante la pubertad, ya que desde la edad prepuberal y etapas precoces del desarrollo pueden aparecer hallazgos clínicos y analíticos de insuficiencia gonadal. No hay un marcador clínico, hormonal o ecográfico suficiente para determinar si existe insuficiencia gonadal, lo que obliga a que el seguimiento se prolongue a la edad adulta., "PUBERTY AND GONADAL FUNCTION ASSESSMENT IN PEDIATRIC SURVIVORS OF A CHILDHOOD CANCER"Background and objectives: Facing a longer survival of children with cancer, there is a growing concern for their follow-up. The objectives are: 1) To extend the knowledge of oncologic treatment's late effects on puberty and gonadal function in pediatric survivors of childhood cancer; 2) To define gonadal function markers in pre, intra and postpubertal children.Patients and methods: A study group and a control group were defined. The former included 7 to 18-year-old survivors of childhood cancer (72 boys and 54 girls). The latter included healthy 7 to 18-year-old children (58 boys and 56 girls). They had a clinical evaluation done, including pubertal development assessment according to Tanner, testicular volume and menstrual cycle. We determined the basal serum concentration of FSH, LH, testosterone, estradiol and inhibin B. Adolescent boys had a seminogram done, and pubertal girls a pelvic ultrasound. Results: Control group: in boys inhibin B increased early at the beginning of puberty, with a negative correlation between FSH and inhibin B from midpuberty. In girls hormones increased during pubertal development with a positive correlation between them. Study group: 6% of boys had a pubertal delay and 15% of girls an advanced or precocious puberty. Comparing the study group versus the control group, stage I and II boys were significantly older. In stage II FSH, LH and testosterone were significantly higher, and in stage III differences for LH and testosterone persisted. In girls there were no differences in profile variables, but in stage I inhibin B was significantly lower. Among boys, 19 (26,4%) had tubular insufficiency, significantly associated with age at treatment and bone marrow transplantation (BMT), and 5 (7%) Leydig cells' insufficiency, significantly associated with radiotherapy and BMT. Among girls, 11 (20,4%) had a partial ovarian insufficiency, significantly associated with radiotherapy, gonadotoxic chemotherapy, BMT and central nervous system tumours.Conclusions: Prepubertal age at the beginning of treatment does not protect against gonadal damage. All children treated of a cancer must be carefully followed up during puberty. There is not a clinical, hormonal or ultrasound marker to determine if there is gonadal insufficiency, which implies that follow-up must continue in adult age.

Made available in DSpace on 2017-06-01T18:08:40Z (GMT). No. of bitstreams: 1 Leda Viana.pdf: 944185 bytes, checksum: 98dc4ffe5bebbc00fe16f8d52ed04244 (MD5) Previous issue date: 2004-01-12 To have a child with cancer and hospitalized is a painful situation to all family. In most cases, is the mother who stays whit the child in the hospital, being her involvement recognized as fundamental for medical treatment and his recovery. That s why, it s necessary an understanding about her real necessities faced with universe of infant cancer. Therefore this study focus on sense of the livings of mothers-being close of children in cancer treatment. This research is quality, with phenomenologic grounding, in which, we used like devices the free observations and mothers-being close talks. In among specialties about the livings of mothers-being close , we highlight some expressions that are shared and told by her: faced with diagnosis cancer, they express feelings of unbelievable, despair and disgust; during the going with her child, the mothers tell to feel fear, helpless; they seek desperately a cause for the sickness of their children; they express grateful to the hospital; they show necessity for obtain information about cancer. We understand the mothers-being close , during the going into the hospital, need, especially, emotion support, effective and systemic careful, so that, can contribute effectively in the treatment and recovery of their children A realidade de ter um filho com câncer e hospitalizado, é uma situação penosa para toda família. Na maioria dos casos, é a mãe que acompanha o internamento, sendo sua participação reconhecida como fundamental no tratamento e recuperação do filho. Para tanto, é necessário uma compreensão de suas reais necessidades frente ao universo do câncer infantil. Este estudo vem focalizar, portanto, o sentido das vivências de mães-acompanhantes de filhos no tratamento do câncer. Trata-se de uma pesquisa qualitativa de base fenomenológica, na qual buscamos trabalhar com observações livres e narrativas de mães que estão vivenciando o acompanhamento ao tratamento de filhos com câncer. Dentre as singularidades dessas vivências, destacamos algumas expressões que são compartilhadas e narradas pelas mães: diante do diagnóstico de câncer, expressam sentimentos de incredulidade, revolta, desespero; na hospitalização, relatam sentir temor, desamparo; buscam incessantemente uma causa para o adoecimento dos filhos; explicitam gratidão pelo hospital; demonstram necessidade de obter informações sobre o câncer. Entendemos que as mães- acompanhantes, durante a internação, necessitam, sobretudo, de suporte emocional, atenção efetiva e sistêmica, para que, assim, possam contribuir ativamente no tratamento e restabelecimento dos filhos

Ankara : Department of Molecular Biology and Genetics and the Institute of Engineering and Science of Bilkent University, 1999. Thesis (Master's) -- Bilkent University, 1999. Includes bibliographical references leaves 79-93 Al-Otaibi, Hani SM M.S.

Las neoplasias infantiles más frecuentes son...

Background: Malignant pleural mesothelioma is a rare, invasive and often fatal neoplasm that develops in the thin layer of tissue surrounding the lungs known as the pleura. Although rare, mesotheliomas do occur in the young; their characteristics are distinct from those of older patients. Case presentation: This is a case report of a 17-year-old boy who had moderate dyspnea, cough, right-sided pleuritic chest pain, fever, headache and no weight loss. Physical examination showed a right pleural effusion and chest roentgenograms revealed a homogenous opacity on lower right hemithorax. Biochemical analysis of pleural fluid showed hemorrhagic/turbid effusion compatible with exudate. It was initially treated as an empyema. The pleural fluid culture was negative. Adenosine deaminase level was 34.3 U/L (admission) and 19.02 U/L (two weeks after). Pleural fluid smear and culture for Mtb were negative. During the open pleural biopsy, thickened pleura and multiple pale yellow nodules in the lung were observed. The histopathological report was compatible with malignant pleural mesothelioma. With this diagnosis, a chemotherapy regimen with cisplatin was initiated. After two cycles, the patient had no clinical and radiological improvement. The patient is currently under regular follow up. Conclusion: MPM is rare in young adults and its clinical presentation makes it different from mesothelioma in elderly patients, so it will be necessary to identify the new risk factors that can identify these patients.