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Changes in epigenetic processes such as histone acetylation are proposed as key events influencing cancer cell function and the initiation and progression of pediatric brain tumors. Valproic acid (VPA) is an antiepileptic drug that acts partially by inhibiting histone deacetylases (HDACs) and could be repurposed as an epigenetic anticancer therapy. Here, we show that VPA reduced medulloblastoma (MB) cell viability and led to cell cycle arrest. These effects were accompanied by enhanced H3K9 histone acetylation (H3K9ac) and decreased expression of the MYC oncogene. VPA impaired the expansion of MB neurospheres enriched in stemness markers, and reduced MYC while increasing TP53 expression in these spheres. In addition, VPA induced morphological changes consistent with neuronal differentiation and increased expression of differentiation marker genes TUBB3 and ENO2 . Expression of stemness genes SOX2 , NES , and PRTG was differentially affected by VPA in MB cells with different TP53 status. VPA increased H3K9 occupancy of the promoter region of TP53 . Among genes regulated by VPA, stemness regulators MYC and NES showed association with patient survival in specific MB subgroups. Our results indicate that VPA may exert antitumor effects in MB by influencing histone acetylation, which may result in modulation of stemness, neuronal differentiation, and expression of genes associated with patient prognosis in specific molecular subgroups. Importantly, the actions of VPA in MB cells and neurospheres include a reduction in expression of MYC and increase in TP53 ., Competing Interests: Conflict of Interest The authors declare no competing interests.

Methotrexate (MTX), which presents high inter-individual variability, is part of the Brazilian Osteosarcoma Treatment Group (BOTG) protocol. This work aimed to develop a MTX population pharmacokinetic model (POPPK) for Brazilian children with osteosarcoma (OS) following the BOTG protocol to guide rescue therapy and avoid toxicity. The model was developed in NONMEM 7.4 (Icon ® ) using retrospective sparse data from MTX therapeutic drug monitoring of children attending a southern Brazilian public reference hospital. Data were described by a two-compartment model using 216 MTX cycles from 32 patients (5-18 y.o.) with OS who received 12 g/m 2 dose/cycle. To explain inter-individual and inter-occasion variability in clearance and peripheral volume, covariates from demographic and biochemical data were evaluated. Serum creatinine was a significant covariate of MTX clearance (14.8 L/h), and the body surface area (BSA) was significant for central compartment volume (82.5 L). Inter-compartmental clearance and volume of peripheral compartment were 0.178 L/h and 5.72 L, respectively. The model adequately describes MTX exposure in Brazilian children with OS. Successful simulations were performed to predict MTX concentrations in pediatric patients above five years old with acute kidney injury and anticipate rescue therapy adjustments.

The aim of the present study was to analyze the relationship of OM with possible risk factors such as oral health condition, immunological status and IL-1β profile in patients submitted to hematopoietic stem cell transplantation (HSCT). Fifty-four individuals submitted to HSCT were included. All patients received previous dental treatment and photobiomodulation (PBM) as the institutional OM preventive protocol. OM scores, immune status, and IL-1β levels were determined during the conditioning period and at D+3 and D+8 after HSC infusion. IL-1β gene polymorphism was also analyzed during conditioning. Possible associations of OM with risk factors were analyzed using conditional Fisher's exact test. OM was observed in 34 patients (62.9%) classified as Grade 1 (13 patients/24.1%), Grade 2 (14 patients/25.9%), Grade 3 (3 patients/5.5%), and Grade 4 (4 patients/7.4%). Allogeneic HSCT individuals exhibited a higher OM grade than autologous subjects. Moreover, an association was observed between severe OM and severe gingivitis (p = 0.01), neutropenia (p = 0.03), and leukopenia (p = 0.04). A significant association between OM and lower IL-1β levels was detected at three time points, i.e., conditioning (p = 0.048), D+3 (p = 0.01), and D+8 (p = 0.005). The results showed that IL-1β gene polymorphism was not associated with OM. Our study provided important insights into the scope of OM risk factors in the setting of HSCT. Patients submitted to HSCT with severe gingivitis prior to chemotherapy and with severe neutropenia and leukopenia exhibited a higher OM grade. Further investigation will be necessary to better understand the exact role of IL-1β in the context of OM pathobiology and to validate cytokine analysis in larger cohorts.

Objective: to determine the expression of neurotrophins and their tyrosine-kinase receptors in patients with osteosarcoma (OS) and their correlation with clinical outcomes., Methods: we applied immunohistochemistry to biopsy specimens of patients consecutively treated for primary OS at a single institution between 2002 and 2015, analyzing them for expression receptors of tyrosine kinase A and B (TrKA and TrKB), neural growth factor (NGF) and brain derived neurotrophic factor (BDNF). Independently, two pathologists classified the immunohistochemical markers as negative (negative or weak focal) or positive (moderate focal/diffuse or strong focal/diffuse)., Results: we analyzed data from 19 patients (10 females and 9 males), with median age of 12 years (5 to 17.3). Tumors' location were 83.3% in the lower limbs, and 63.2% of patients had metastases at diagnosis. Five-year overall survival was 55.3%. BDNF was positive in 16 patients (84%) and NGF in 14 (73%). TrKA and TrKB presented positive staining in four (21,1%) and eight (42,1%) patients, respectively. Survival analysis showed no significant difference between TrK receptors and neurotrophins., Conclusion: primary OS samples express neurotrophins and TrK receptors by immunohistochemistry. Future studies should explore their role in OS pathogenesis and determine their prognostic significance in larger cohorts.

Ewing Sarcoma (ES) is a highly aggressive bone and soft tissue childhood cancer. The development of resistance to chemotherapy is common and remains the main cause of treatment failure. We herein evaluated the expression of genes associated with chemotherapy resistance in ES cell lines. A set of genes (CCAR1, TUBA1A, POLDIP2, SMARCA4 and SMARCB1) was data-mined for resistance against doxorubicin and vincristine, which are the standard drugs used in the treatment of patients with ES. The expression of each gene in SK-ES-1 ES cells was reported before and after exposure to a drug resistance-inducing protocol. There was a significant downregulation of CCAR1 and TUBA1A in doxorubicin-resistant cells, with low expression of TUBA1A in vincristine-resistant cells. By contrast, POLDIP2 was significantly upregulated in cells resistant to either drug, and the expression of the SMARCB1 and SMARCA4 genes was upregulated in doxorubicin-resistant cells. These findings indicate that resistance to specific chemotherapeutic agents was accompanied by differential changes in gene expression in ES tumors.

Background: Relapse in localized Ewing sarcoma patients has been a matter of concern regarding poor prognosis. Therefore, we investigated the impact of local control modality (surgery, surgery plus radiotherapy, and radiotherapy) on clinical outcomes such as survival and recurrence in patients with non-metastatic Ewing sarcoma treated on the first Brazilian Collaborative Group Trial of the Ewing Family of Tumors (EWING1)., Methods: Seventy-three patients with localized Ewing sarcoma of bone aged < 30 years were included. The treating physicians defined the modality of local control based on the recommendations of the coordinating center and the patient and tumor characteristics. Possible associations of local control modality with local failure (LF), disease-free survival (DFS), event-free survival (EFS), overall survival (OS), and clinical characteristics were analyzed., Results: Mean patient age was 12.8 years (range, 2 to 25 years) and median follow-up time was 4.5 years (range, 2.3 to 6.7 years). Forty-seven patients underwent surgery, 13 received radiotherapy, and 13 received both. The 5-year EFS, OS, and DFS for all patients was 62.1%, 63.3%, and 73.1%, respectively. The 5-year cumulative incidence (CI) of LF was 7.6% for surgery, 11.1% for radiotherapy, and 0% for postoperative radiotherapy (PORT) (p = 0.61). The 5-year EFS was 71.7% for surgery, 30.8% for radiotherapy, and 64.1% for PORT (p = 0.009)., Conclusions: There was a significant effect of local control modality on EFS and OS in the study. Surgery and PORT modalities yielded very close results. The group treated with radiotherapy alone had considerably worse outcomes. This may be confounded by greater risk factors in these patients. There was no significant effect of local control modality on the CI of LF and DFS.

Objective: To describe survival and neurological outcomes after HSCT for these disorders., Methods: Seven CALD, 2 MLD and 2 MPS-IH patients underwent HSCT between 2007 and 2014. Neurological examinations, magnetic resonance imaging, molecular and biochemical studies were obtained at baseline and repeated when appropriated., Results: Favorable outcomes were obtained with 4/5 related and 3/6 unrelated donors. Two patients died from procedure-related complications. Nine transplanted patients were alive after a median of 3.7 years: neurological stabilization was obtained in 5/6 CALD, 1/2 MLD, and one MPS-IH patient. Brain lesions of the MPS-IH patient were reduced four years after HSCT., Conclusion: Good outcomes were obtained when HSCT was performed before adulthood, early in the clinical course, and/or from a related donor.

Ewing sarcoma (ES) is a highly aggressive pediatric cancer that may arise from neuronal precursors. Neurotrophins stimulate neuronal devlopment and plasticity. Here, we found that neurotrophins nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), as well as their receptors (TrkA and TrkB, respectively) are expressed in ES tumors. Treatment with TrkA (GW-441756) or TrkB (Ana-12) selective inhibitors decreased ES cell proliferation, and the effect was increased when the two inhibitors were combined. ES cells treated with a pan-Trk inhibitor, K252a, showed changes in morphology, reduced levels of β-III tubulin, and decreased mRNA expression of NGF, BDNF, TrkA and TrkB. Furthermore, combining K252a with subeffective doses of cytotoxic chemotherapeutic drugs resulted in a decrease in ES cell proliferation and colony formation, even in chemoresistant cells. These results indicate that Trk inhibition may be an emerging approach for the treatment of ES., Competing Interests: The authors declare no conflicts of interest.

Objective: To compare the use of intravenous vs. oral antibiotic therapy., Methods: All febrile neutropenic patients younger than 18 years old with low risk of complications and receiving chemotherapy were selected. The study was conducted from 2002 to 2005 at the Pediatric Oncology Unit of Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil. Patients were divided into group A and group B and were randomly assigned to receive oral or intravenous therapy. The empirical antimicrobial treatment used for group A consisted in oral ciprofloxacin plus amoxicillin-clavulanate and intravenous placebo, and group B received cefepime and oral placebo., Results: A total of 91 consecutive episodes of febrile neutropenia in 58 children were included in the study. For patients of group A, treatment failure rate was 51.2%; the mean length of hospital stay was 8 days (range 2-10 days). For patients treated with intravenous antibiotic therapy, treatment failure rate was 45.8%; the mean length of hospital stay was 7 days (range 3-10 days)., Conclusion: There was no difference in the outcome in oral vs. intravenous therapy. There is need of larger randomized trials before oral empirical therapy administered to this population should be considered the new standard of treatment.

Objective: To describe the demographics and the most important acute clinical complications in patients undergoing bone marrow transplantation in the Pediatric Oncology Unit at Hospital de Clínicas de Porto Alegre, Brazil., Material and Methods: A retrospective analysis was performed including 41 patients treated between August 1997 and June 2002. Twenty patients received allogeneic transplants (AG) and 21 received autologous transplants (AT)., Results: The mean age of AG patients was 8.9 +/- 5.4 years. Twelve patients were male. Stem cell sources were: bone marrow in 12 patients; peripheral blood in five; and unrelated cord blood in three. The diseases were acute lymphoid leukemia in seven patients; acute myeloid leukemia in four; chronic myeloid leukemia in two; myelodysplastic syndrome in two; Burkitt's lymphoma in one; severe combined immunodeficiency in one; Chediaki-Higashi syndrome in one; Fanconi anemia in one; and aplastic anemia in one. One patient developed grade II acute graft-versus-host-disease (GVHD), and three patients had grade IV GVHD. Three patients developed chronic GVHD. In all of them, the cell source was peripheral blood. Survival in this group was 70.0 +/- 10.3%. The main cause of death was GVHD in three patients and sepsis in another three. All deaths occurred before day 100. One of the patients who received unrelated cord blood is alive 3.5 years after the transplantation. In AG patients, mean age was 8.7 +/- 4.3 years. Eleven patients were male. The stem cell sources were: peripheral blood in 16; bone marrow in three; and peripheral blood + bone marrow in two. The diseases were: Wilms' tumor in five patients; Ewing's sarcoma family tumors in four; neuroblastoma in three; Hodgkin's disease in three; non-Hodgkin's lymphoma in one; rhabdomyosarcoma in two; neuroectodermic tumor of the central nervous system in two; acute myeloid leukemia in one. Survival in this group was 59.4 +/- 11.7%. Five patients died due to tumor relapse, two patients due to sepsis and one patient died in remission 20 months after bone marrow transplantation due to infection. In the whole group, the most common toxicities were vomiting, mucositis, diarrhea and abdominal pain. Infections were recorded in 58.5% of the patients. In 46.9%, at least one pathogen was isolated in the blood culture. The time required for neutrophil and platelet engraftment was correlated to the number of hematopoietic stem cell infused., Conclusion: The overall survival in our patients is similar to that reported in the literature. We did not find differences between AT and AG patients regarding acute toxicities and infections.

Background: The purpose of this phase I study was to evaluate the toxicity profile, dose-limiting toxicities (DLT), maximum tolerated dose (MTD), and plasma pharmacokinetics of oral etoposide, and to recommend a safe fractionated dose for phase II trials in pediatric patients with refractory solid tumors., Material/methods: All patients had tumors no longer amenable to established forms of treatment. The initial dose of etoposide was 20 mg/m(2) TID for 14 days every 21 days (dose-level I). Etoposide plasma pharmacokinetics were studied on day 1 of treatment and determined by HPLC., Results: Seventeen children were enrolled, 13 of whom were included in the pharmacokinetic study, for a total of 64 courses. Nine patients were included at dose-level I; grade 2-3 leucopenia was observed in 5. The dose was then raised to 25 mg/m(2) (dose-level II) in another 8 patients; grade 3-4 leucopenia was observed in 4. This dose-level was therefore considered the MTD. The DLT was neutropenia. In patients at dose-level I and II the maximum plasma etoposide concentration was 2.97 and 8.59 mg/ml, respectively. Drug levels > 1 microg/ml were maintained for about 6.3 hours following drug administration at both dose-levels. Partial response was observed in 1 patient and 4 patients showed stable disease., Conclusions: Prolonged oral etoposide was well tolerated by our patients. Considering the MTD, and the fact that the patients included at dose-level I achieved an adequate (>1 microg/ml) plasma concentration of etoposide for a sufficient time, this dose level was recommended for phase II studies in pediatric malignancies.

OBJECTIVE: To review the indications, main steps and complications of bone marrow transplantation in children. SOURCES: Medline-based literature review. SUMMARY OF THE FINDINGS: We comment about the indications of autologous, allogeneic and syngeneic bone marrow transplantation, donor selections, harvest and infusion of the hematopoietic progenitor cells that will reconstitute the hematopoietic and immune systems. We describe the different conditioning regimens and the new sources of cells, such as cord blood. We also describe the most common events after the procedure, including infections, graft versus host disease, and cardiovascular, pulmonary, hepatic, genitourinary, and gastrointestinal complications. The late effects and their impact on quality of life are also discussed. CONCLUSIONS: Bone marrow transplantation does not confer an absolutely normal life span to all the patients; however, it represents the only chance of cure for children with certain neoplastic or immunological diseases. By knowing the steps of the procedure, pediatricians can be a source of information on bone marrow transplantation to the patients and their families.