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The portal of entry of disseminated Fusarium spp. infections is still not clearly defined. We report on a disseminated Fusarium oxysporum infection occurring during a long period of severe neutropenia in a child with hemophagocytic lymphohistiocytosis. A nasogastric feeding tube was the possible source of entry of the fungus. [ABSTRACT FROM AUTHOR]

Background: Radiotherapy (RT) has become an important treatment modality in pediatric oncology, but its delivery to young children with cancer is challenging and general anesthesia is often needed.Methods: To evaluate whether a psychoeducational intervention might reduce the need for anesthesia, 223 consecutive pediatric cancer patients receiving 4141 RT fractions during 244 RT courses between February 1989 and January 2006 were studied. Whereas in 154 RT courses corresponding with 2580 RT fractions patients received no psychoeducational intervention (group A), 90 RT courses respectively 1561 RT fractions were accomplished by using psychoeducational intervention (group B). This tailored psychoeducational intervention in group B included a play program and interactive support by a trained nurse according to age to get familiar with staff, equipment and procedure of radiotherapy.Results: Group A did not differ significantly from group B in age at RT, gender, diagnosis, localization of RT and positioning during RT. Whereas 33 (21.4%) patients in group A got anesthesia, only 8 (8.9%) patients in group B needed anesthesia. The median age of cooperating patients without anesthesia decreased from 3.2 to 2.7 years. In both uni- and multivariate analyses the psychoeducational intervention significantly and independently reduced the need for anesthesia.Conclusion: We conclude that a specifically tailored psychoeducational intervention is able to reduce the need for anesthesia in children undergoing RT for cancer. This results in lower costs and increased cooperation during RT. [ABSTRACT FROM AUTHOR]

As the second most common pediatric bone and soft tissue tumor, Ewing sarcoma (ES) is an aggressive disease with a pathognomonic chromosomal translocation t(11;22) resulting in expression of EWS-FLI1, an "undruggable" fusion protein acting as transcriptional modulator. EWS-FLI1 rewires the protein expression in cancer cells by activating and repressing a multitude of genes. The role and contribution of most repressed genes remains unknown to date. To address this, we established a CRISPR activation system in clonal SKNMC cell lines and interrogated a custom focused library covering 871 genes repressed by EWS-FLI1. Among the hits several members of the TGFβ pathway were identified, where PEG10 emerged as prime candidate due to its strong antiproliferative effect. Mechanistic investigations revealed that PEG10 overexpression caused cellular dropout via induction of cell death. Furthermore, non-canonical TGFβ pathways such as RAF/MEK/ERK, MKK/JNK, MKK/P38, known to lead to apoptosis or autophagy, were highly activated upon PEG10 overexpression. Our study sheds new light onto the contribution of TGFβ signalling pathway repression to ES tumorigenesis and suggest that its re-activation might constitute a novel therapeutic strategy., (© 2022. The Author(s).)

Endemic Burkitt lymphoma (eBL) is an aggressive B cell cancer characterized by an IgH/c-myc translocation and the harboring of Epstein-Barr virus (EBV). Evidence accumulates that CD4 + T cells might contribute to eBL pathogenesis. Here, we investigate the presence of CD4 + T cells in primary eBL tissue and their potential dichotomous impact on an EBV-infected pre-eBL cell model using ex vivo material and in vitro co-cultures. In addition, we establish a novel method to study the effect of IgH/c-myc translocation in primary B cells by employing a CRISPR/Cas9 knock-in approach to introduce and tag de novo translocation. We unprecedently document that CD4 + T cells are present in primary eBL tumor tissue. Furthermore, we demonstrate that CD4 + T cells on the one hand suppress eBL development by killing pre-eBL cells lacking IgH/c-myc translocation in vitro and on the other hand indirectly promote eBL development by inducing crucial EBV Latency III to Latency I switching in pre-eBL cells. Finally, we show that while the mere presence of an IgH/c-myc translocation does not suffice to escape CD4 + T-cell-mediated killing in vitro, the CD4 + T-cell-mediated suppression of EBV's Latency III program in vivo may allow cells harboring an IgH/c-myc translocation and additional mutations to evade immune control and proliferate by means of deregulated c-myc activity, resulting in neoplasia. Thus, our study highlights the dichotomous effects of CD4 + T cells and the mechanisms involved in eBL pathogenesis, suggests mechanisms of their impact on eBL progression, and provides a novel in vitro model for further investigation of IgH/c-myc translocation., (© 2021. The Author(s).)

Oncogenic transcription factors lacking enzymatic activity or targetable binding pockets are typically considered "undruggable". An example is provided by the EWS-FLI1 oncoprotein, whose continuous expression and activity as transcription factor are critically required for Ewing sarcoma tumor formation, maintenance, and proliferation. Because neither upstream nor downstream targets have so far disabled its oncogenic potential, we performed a high-throughput drug screen (HTS), enriched for FDA-approved drugs, coupled to a Global Protein Stability (GPS) approach to identify novel compounds capable to destabilize EWS-FLI1 protein by enhancing its degradation through the ubiquitin-proteasome system. The protein stability screen revealed the dual histone deacetylase (HDAC) and phosphatidylinositol-3-kinase (PI3K) inhibitor called fimepinostat (CUDC-907) as top candidate to modulate EWS-FLI1 stability. Fimepinostat strongly reduced EWS-FLI1 protein abundance, reduced viability of several Ewing sarcoma cell lines and PDX-derived primary cells and delayed tumor growth in a xenograft mouse model, whereas it did not significantly affect healthy cells. Mechanistically, we demonstrated that EWS-FLI1 protein levels were mainly regulated by fimepinostat's HDAC activity. Our study demonstrates that HTS combined to GPS is a reliable approach to identify drug candidates able to modulate stability of EWS-FLI1 and lays new ground for the development of novel therapeutic strategies aimed to reduce Ewing sarcoma tumor progression., Competing Interests: Declaration of Competing Interest The authors declare no potential conflicts of interests., (Copyright © 2022. Published by Elsevier Inc.)

Cancer therapy is currently shifting from broadly used cytotoxic drugs to patient-specific precision therapies. Druggable driver oncogenes, identified by molecular analyses, are present in only a subset of patients. Functional profiling of primary tumor cells could circumvent these limitations, but suitable platforms are unavailable for most cancer entities. Here, we describe an in vitro drug profiling platform for rhabdomyosarcoma (RMS), using a living biobank composed of twenty RMS patient-derived xenografts (PDX) for high-throughput drug testing. Optimized in vitro conditions preserve phenotypic and molecular characteristics of primary PDX cells and are compatible with propagation of cells directly isolated from patient tumors. Besides a heterogeneous spectrum of responses of largely patient-specific vulnerabilities, profiling with a large drug library reveals a strong sensitivity towards AKT inhibitors in a subgroup of RMS. Overall, our study highlights the feasibility of in vitro drug profiling of primary RMS for patient-specific treatment selection in a co-clinical setting.

Ewing sarcoma is the second most common pediatric bone and soft tissue tumor presenting with an aggressive behavior and prevalence to metastasize. The diagnostic translocation t(22;11)(q24;12) leads to expression of the chimeric oncoprotein EWS-FLI1 which is uniquely expressed in all tumor cells and maintains their survival. Constant EWS-FLI1 protein turnover is regulated by the ubiquitin proteasome system. Here, we now identified ubiquitin specific protease 19 (USP19) as a regulator of EWS-FLI1 stability using an siRNA based screening approach. Depletion of USP19 resulted in diminished EWS-FLI1 protein levels and, vice versa, upregulation of active USP19 stabilized the fusion protein. Importantly, stabilization appears to be specific for the fusion protein as it could not be observed neither for EWSR1 nor for FLI1 wild type proteins even though USP19 binds to the N-terminal EWS region to regulate deubiquitination of both EWS-FLI1 and EWSR1. Further, stable shUSP19 depletion resulted in decreased cell growth and diminished colony forming capacity in vitro, and significantly delayed tumor growth in vivo. Our findings not only provide novel insights into the importance of the N-terminal EWSR1 domain for regulation of fusion protein stability, but also indicate that inhibition of deubiquitinating enzyme(s) might constitute a novel therapeutic strategy in treatment of Ewing sarcoma.

E-26 transformation-specific (ETS) proteins are transcription factors directing gene expression through their conserved DNA binding domain. They are implicated as truncated forms or interchromosomal rearrangements in a variety of tumors including Ewing sarcoma, a pediatric tumor of the bone. Tumor cells express the chimeric oncoprotein EWS-FLI1 from a specific t(22;11)(q24;12) translocation. EWS-FLI1 harbors a strong transactivation domain from EWSR1 and the DNA-binding ETS domain of FLI1 in the C-terminal part of the protein. Although Ewing cells are crucially dependent on continuous expression of EWS-FLI1, its regulation of turnover has not been characterized in detail. Here, we identify the EWS-FLI1 protein as a substrate of the ubiquitin-proteasome system with a characteristic polyubiquitination pattern. Using a global protein stability approach, we determined the half-life of EWS-FLI1 to lie between 2 and 4 h, whereas full-length EWSR1 and FLI1 were more stable. By mass spectrometry, we identified two ubiquitin acceptor lysine residues of which only mutation of Lys-380 in the ETS domain of the FLI1 part abolished EWS-FLI1 ubiquitination and stabilized the protein posttranslationally. Expression of this highly stable mutant protein in Ewing cells while simultaneously depleting the endogenous wild type protein differentially modulates two subgroups of target genes to be either EWS-FLI1 protein-dependent or turnover-dependent. The majority of target genes are in an unaltered state and cannot be further activated. Our study provides novel insights into EWS-FLI1 turnover, a critical pathway in Ewing sarcoma pathogenesis, and lays new ground to develop novel therapeutic strategies in Ewing sarcoma., (© 2016 by The American Society for Biochemistry and Molecular Biology, Inc.)

Background: Parameningeal rhabdomyosarcomas (PM-RMSs) represent approximately 25% of all rhabdomyosarcoma (RMS) cases. These tumors are associated with early recurrence and poor prognosis. This study assessed the clinical outcome and late toxicity of pencil beam scanning (PBS) proton therapy (PT) in the treatment of children with PM-RMS., Procedures: Thirty-nine children with PM-RMS received neoadjuvant chemotherapy followed by PBS-PT at the Paul Scherrer Institute, with concomitant chemotherapy. The median age was 5.8 years (range, 1.2-16.1). Due to young age, 25 patients (64%) required general anesthesia during PT. The median time from the start of chemotherapy to PT was 13 weeks (range, 3-23 weeks). Median prescription dose was 54 Gy (relative biologic effectiveness, RBE)., Results: With a mean follow-up of 41 months (range, 9-106 months), 10 patients failed. The actuarial 5-year progression-free survival (PFS) was 72% (95% CI, 67-94%) and the 5-year overall survival was 73% (95% CI, 69-96%). On univariate analysis, a delay in the initiation of PT (>13 weeks) was a significant detrimental factor for PFS. Three (8%) patients presented with grade 3 radiation-induced toxicity. The estimated actuarial 5-year toxicity ≥grade 3 free survival was 95% (95% CI, 94-96%)., Conclusions: Our data contribute to the growing body of evidence demonstrating the safety and effectiveness of PT for pediatric patients with PM-RMS. These preliminary results are encouraging and in line with other combined proton-photon and photons series; observed toxicity was acceptable., (© 2015 Wiley Periodicals, Inc.)

Ewing sarcomas (ES) are highly malignant bone or soft tissue tumors. Genetically, ES are defined by balanced chromosomal EWS/ETS translocations, which give rise to chimeric proteins (EWS-ETS) that generate an oncogenic transcriptional program associated with altered epigenetic marks throughout the genome. By use of an inhibitor (JQ1) blocking BET bromodomain binding proteins (BRDs) we strikingly observed a strong down-regulation of the predominant EWS-ETS protein EWS-FLI1 in a dose dependent manner. This was further enhanced by co-treatment with an inhibitor of the PI3K pathway. Microarray analysis further revealed JQ1 treatment to block a typical ES associated expression program. The effect on this expression program was mimicked by RNA interference with BRD3 or BRD4 expression, indicating that the EWS-FLI1 mediated expression profile is at least in part mediated via such epigenetic readers. Consequently, contact dependent and independent proliferation of different ES lines was strongly inhibited. Mechanistically, treatment of ES resulted in a partial arrest of the cell cycle as well as induction of apoptosis. Tumor development was suppressed dose dependently in a xeno-transplant model in immune deficient mice, overall indicating that ES may be susceptible to treatment with epigenetic inhibitors blocking BET bromodomain activity and the associated pathognomonic EWS-ETS transcriptional program.

Ewing sarcoma (ES) is the second most frequent bone cancer in childhood and is characterized by the presence of the balanced translocation t(11;22)(q24;q12) in more than 85% of cases, generating a dysregulated transcription factor EWS/FLI1. This fusion protein is an essential oncogenic component of ES development which is necessary for tumor cell maintenance and represents an attractive therapeutic target. To search for modulators of EWS/FLI1 activity we screened a library of 153 targeted compounds and identified inhibitors of the PI3K pathway to directly modulate EWS/FLI1 transcription. Surprisingly, treatment of four different ES cell lines with BEZ235 resulted in down regulation of EWS/FLI1 mRNA and protein by ~50% with subsequent modulation of target gene expression. Analysis of the EWS/FLI1 promoter region (-2239/+67) using various deletion constructs identified two 14 bp minimal elements as being important for EWS/FLI1 transcription. We identified SP1 as modulator of EWS/FLI1 gene expression and demonstrated direct binding to one of these regions in the EWS/FLI1 promoter by EMSA and ChIP experiments. These results provide the first insights on the transcriptional regulation of EWS/FLI1, an area that has not been investigated so far, and offer an additional molecular explanation for the known sensitivity of ES cell lines to PI3K inhibition.

Background: In children and adolescents with fever in neutropenia (FN) during chemotherapy for cancer, hemoglobin ≥90 g/L at presentation with FN had been associated with adverse events (AE). This analysis explored three hypothetical pathophysiological mechanisms potentially explaining this counterintuitive finding, and further analyzed the statistical association between hemoglobin and AE., Methods: Two of 8 centers, reporting on 311 of 421 FN episodes in 138 of 215 patients participated in this retrospective analysis based on prospectively collected data from three databases (SPOG 2003 FN, transfusion and hematology laboratories). Associations with AE were analyzed using mixed logistic regression., Results: Hemoglobin was ≥90 g/L in 141 (45%) of 311 FN episodes, specifically in 59/103 (57%) episodes with AE, and in 82/208 (39%) without (OR, 2.3; 99%CI, 1.1-4.9; P = 0.004). In FN with AE, hemoglobin was bimodally distributed with a dip around 85 g/L. There were no significant interactions for center, age and sex. In multivariate mixed logistic regression, AE was significantly and independently associated with leukopenia (leukocytes <0.3 G/L; OR, 3.3; 99%CI, 1.1-99; P = 0.004), dehydration (hemoglobinPresentation/hemoglobin8-72 hours ≥1.10 in untransfused patients; OR, 3.5; 99%CI, 1.1-11.4; P = 0.006) and non-moderate anemia (difference from 85 g/L; 1.6 per 10 g/L; 1.0-2.6; P = 0.005), but not with recent transfusion of packed red blood cells (pRBC), very recent transfusion of pRBC or platelets, or with hemoglobin ≥90 g/L as such., Conclusions: Non-moderate anemia and dehydration were significantly and relevantly associated with the risk of AE in children with cancer and FN. These results need validation in prospective cohorts before clinical implementation.

Objective: To analyze the clinical course, treatment, complications, outcome, and quality of life (QOL) in patients with perineal/perianal rhabdomyosarcoma (PRMS) treated within the CWS-86, -91, -96, and -2002P trials., Background: Although multiple international study trials exist for the treatment of rhabdomyosarcoma, only very limited information is given on treatment, outcome, and QOL in PRMS., Methods: A total of 35 patients suffering from PRMS were treated with neoadjuvant chemotherapy. Local therapy with radiation and/or surgery was performed, followed by adjuvant chemotherapy. Functional long-term follow-up was evaluated by a gastrointestinal/QOL survey., Results: Thirty-two patients were evaluated (exclusion n = 3). Eight patients had embryonal histology, and 24 patients had alveolar histology. The median age was 108 months (median follow-up: 5.8 years). The 5-year overall survival was 47% (95% confidence interval: 29-64). Sixteen IRS (Intergroup Rhabdomyosarcoma Study) III and IV patients had locoregional lymph node involvement at diagnosis. Seven patients were treated with chemotherapy/surgery alone [5-year event-free survival (EFS): 85.7%]. Eleven patients received only radiochemotherapy (5-year EFS: 27.3%). Combined radiochemotherapy/surgery was used in 12 patients (5-year EFS: 63.6%). Two patients were treated only with chemotherapy and they died. Patients with embryonal histology had a significantly better 5-year EFS (87.5%) than patients with alveolar histology (39.1%; P = 0.013). Some patients reported symptoms of fecal incontinence. The median Wexner fecal incontinence score was 9 (possible range: 0-20), and the median QOL score was 90.5 (applicable range: 0-144)., Conclusions: The outcome of these patients remains unsatisfactory. Prognostic factors for a favorable outcome are tumor size of smaller than 5 cm, negative locoregional lymph nodes, age less than 10 years, low IRS group, and embryonal histology. Fecal incontinence seems to be a problem.

Purpose: We aimed to (1) describe the utilization of mental health-care in survivors and siblings, the association with severity of distress, and visits to other professionals in distressed survivors not utilizing mental health-care; and (2) identify factors associated with utilization of mental health-care in distressed survivors., Methods: Within the Swiss Childhood Cancer Survivor Study, we sent postal questionnaires to all participants aged <16 years at diagnosis (1976-2003), who survived ≥5 years after diagnosis and were aged ≥16 years at study. Survivors and siblings could indicate if they utilized mental health-care in the past year. Psychological distress was assessed with the Brief Symptom Inventory-18 (BSI-18). Participants with scores T ≥ 57 on two of three scales or the Global Severity Index were considered distressed., Results: We included 1,602 survivors and 703 siblings. Overall, 160 (10 %) and 53 (8 %), utilized mental health-care and 203 (14 %) and 127 (14 %) were considered distressed. Among these, 69 (34 %) survivors and 20 (24 %) siblings had utilized mental health-care. Participants with higher distress were more likely to utilize mental health-care. Distressed survivors not utilizing mental health-care were more likely to see a medical specialist than nondistressed. In the multivariable regression, factors associated with utilizing mental health-care were higher psychological distress and reporting late effects., Conclusions: Our results underline the importance of developing interventional programs and implementing psychological screening in follow-up of survivors. It is also important to systematically address siblings' needs. In follow-up, patients at risk should be informed about existing possibilities or advised to visit mental health professionals.

Background: It is unknown whether serum concentrations of mannan-binding lectin (MBL) and MBL-associated serine protease-2 (MASP-2) influence the risk of adverse events (AEs) in children with cancer presenting with fever in neutropenia (FN)., Methods: Pediatric patients with cancer presenting with FN after non-myeloablative chemotherapy were observed in a prospective multicenter study. Mannan-binding lectin and MASP-2 were measured using commercially available enzyme-linked immunosorbent assay in serum taken at cancer diagnosis. Multiple FN episodes per patient were allowed. Associations of MBL and MASP-2 with AE in general, with bacteremia, and with serious medical complications (SMC) during FN were analyzed using mixed logistic regression., Results: Of 278 FN episodes, AE was reported in 84 (30%), bacteremia was reported in 42 (15%), and SMC was reported in 16 (5.8%). Median MBL was 2152 ng/mL (range, 7-10 060). It was very low (<100) in 11 (9%) patients, low (100-999) in 36 (29%) patients, and normal (≥1000) in 79 (63%) patients. Median MASP-2 was 410 ng/mL (range, 68-2771). It was low (<200) in 18 (14%) patients and normal in the remaining 108 (86%) patients. Mannan-binding lectin and MASP-2 were not significantly associated with AE or bacteremia. Normal versus low MBL was independently associated with a significantly higher risk of SMC (multivariate odds ratio, 12.8; 95% confidence interval, 1.01-163; P = .050)., Conclusions: Mannan-binding lectin and MASP-2 serum concentrations were not found to predict the risk to develop AEs or bacteremia during FN. Normal MBL was associated with an increased risk of SMC during FN. This finding, in line with earlier studies, does not support the concept of MBL supplementation in MBL-deficient children with cancer presenting with FN., (© The Author 2013. Published by Oxford University Press on behalf of the Pediatric Infectious Diseases Society. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.)

Background: The definition of fever, and thus fever and neutropenia (FN), varies between different pediatric oncology centers. Higher temperature limit should reduce FN rates, but may increase rates of FN with complications by delaying therapy. This study determined if different fever definitions are associated with different FN rates., Procedure: Two pediatric oncology centers had used three fever definitions in 2004-2011: ear temperature ≥38.5 °C persisting ≥2 hours (low definition); axillary temperature ≥38.5 °C ≥ 2 hours or ≥39.0 °C once (middle); and ear temperature ≥39.0 °C once (high). Clinical information was retrospectively extracted from charts. FN rates were compared using mixed Poisson regression., Results: In 521 pediatric patients with cancer, 783 FN were recorded during 6,009 months cumulative chemotherapy exposure time (501 years; rate, 0.13/month [95% CI, 0.12-0.14]), 124 of them with bacteremia (16%; 0.021/month [0.017-0.025]). In univariate analysis, the high versus low fever definition was associated with a lower FN rate (0.10/month [0.08-0.11] vs. 0.15/month [0.13-0.16]; rate ratio, 0.66 [0.45-0.97]; P = 0.036), the middle definition was intermediate (0.13/month [0.11-0.15]). This difference was not confirmed in multivariate analysis (rate ratio, 0.94 [0.67-1.33]; P = 0.74). The high versus low definition was not associated with an increased rate of FN with bacteremia (multivariate rate ratio, 1.39 [0.53-3.62]; P = 0.50)., Conclusion: A higher fever definition was not associated with a lower FN rate, nor with an increased rate of FN with bacteremia. These may be false negative findings due to methodological limitations. These questions, with their potential impact on health-related quality of life, and on costs, need to be assessed in prospective studies., (Copyright © 2012 Wiley Periodicals, Inc.)

Ewing's sarcoma family of tumors (EFT) is characterized by the presence of chromosomal translocations leading to the expression of oncogenic transcription factors such as, in the majority of cases, EWS/FLI1. Because of its key role in Ewing's sarcoma development and maintenance, EWS/FLI1 represents an attractive therapeutic target. Here, we characterize PHLDA1 as a novel direct target gene whose expression is repressed by EWS/FLI1. Using this gene and additional specific well-characterized target genes such as NROB1, NKX2.2 and CAV1, all activated by EWS/FLI1, as a read-out system, we screened a small-molecule compound library enriched for FDA-approved drugs that modulated the expression of EWS/FLI1 target genes. Among a hit-list of nine well-known drugs such as camptothecin, fenretinide, etoposide and doxorubicin, we also identified the kinase inhibitor midostaurin (PKC412). Subsequent experiments demonstrated that midostaurin is able to induce apoptosis in a panel of six Ewing's sarcoma cell lines in vitro and can significantly suppress xenograft tumor growth in vivo. These results suggest that midostaurin might be a novel drug that is active against Ewing's cells, which might act by modulating the expression of EWS/FLI1 target genes., (Copyright © 2012 UICC.)

Background: The standard treatment of fever in chemotherapy-induced neutropenia (FN) includes emergency hospitalization and empirical intravenous antimicrobial therapy. This study determined if first-day step-down to oral outpatient treatment is not inferior to continued standard regarding safety and efficacy in children with low-risk FN., Procedure: In a randomized controlled non-blinded multicenter study, pediatric patients with FN after non-myeloablative chemotherapy were reassessed after 8-22 hours of inpatient intravenous antimicrobial therapy. Low-risk patients were randomized to first-day step-down to experimental (outpatient, oral amoxicillin plus ciprofloxacin) versus continued standard treatment. Exact non-inferiority tests were used for safety (no serious medical complication; non-inferiority margin of difference, 3.5%) and efficacy (resolution of infection without recurrence, no modification of antimicrobial therapy, no adverse event; 10%)., Results: In 93 (26%) of 355 potentially eligible FN episodes low-risk criteria were fulfilled, and 62 were randomized, 28 to experimental (1 lost to follow-up) and 34 to standard treatment. In intention-to-treat analyses, non-inferiority was not proven for safety [27 of 27 (100%) vs. 33 of 34 (97%; 1 death) episodes; 95% upper confidence border, 6.7%; P = 0.11], but non-inferiority was proven for efficacy [23 of 27 (85%) vs. 26 of 34 (76%) episodes; 95% upper confidence border, 9.4%; P = 0.045]. Per-protocol analyses confirmed these results., Conclusions: In children with low-risk FN, the efficacy of first-day step-down to oral antimicrobial therapy with amoxicillin and ciprofloxacin in an outpatient setting was non-inferior to continued hospitalization and intravenous antimicrobial therapy. The safety of this procedure, however, was not assessable with sufficient power., (Copyright © 2012 Wiley Periodicals, Inc.)

Background: Fever and chemotherapy-induced neutropenia (FN) is the most frequent potentially lethal complication of therapy in children with cancer. This study aimed to describe serious medical complications (SMC) in children with FN regarding incidence, clinical spectrum, and associated characteristics., Procedure: Pediatric patients presenting with FN induced by non-myeloablative chemotherapy were observed in a prospective multicenter study. SMC was defined as potentially life-threatening complication (PLTC), transfer to the pediatric intensive care unit (PICU), or death., Results: A total of 443 FN episodes were reported from 8 centers. Of these, 411 episodes were reported from 4 centers recruiting consecutively and without bias regarding the risk of complications. They were used for calculation of proportions. An SMC was reported in 23 episodes [5.6%; 95% confidence interval (CI): 3.7-8.1], usually defined by more than one criterion. These were PLTC in 13 episodes, PICU in 22, and death in 3 (mortality, 0.7%; 95% CI: 0.2-2.1). Both a delayed onset of SMC (14 of 23 episodes, 61%) and a biphasic clinical course (11 of 23, 48%) were frequently observed. In a multivariate logistic regression analysis, 4 characteristics were significantly and independently associated with the risk of SMC: diagnosis of acute myeloid leukemia, interval since chemotherapy ≤7 days, severely reduced general condition, and hemoglobin ≥9.0 g/dl at presentation., Conclusions: In children with FN, SMC were rare, and mortality was very low. Those with SMC often had a delayed onset and biphasic clinical course with secondary deterioration., (Copyright © 2011 Wiley Periodicals, Inc.)

Background: Relapses occur in about 20% of children with acute lymphoblastic leukemia (ALL). Approximately one-third of these children can be cured. Their risk for late effects is high because of intensified treatment, but their health-related quality of life (HRQOL) was largely unmeasured. Our aim was to compare HRQOL of ALL survivors with the general population, and of relapsed with non-relapsed ALL survivors., Methodology/principal Findings: As part of the Swiss Childhood Cancer Survivor Study (SCCSS) we sent a questionnaire to all ALL survivors in Switzerland who had been diagnosed between 1976-2003 at age <16 years, survived ≥5 years, and were currently aged ≥16 years. HRQOL was assessed with the Short Form-36 (SF-36), which measures four aspects of physical health and four aspects of mental health. A score of 50 corresponded to the mean of a healthy reference population. We analyzed data from 457 ALL survivors (response: 79%). Sixty-one survivors had suffered a relapse. Compared to the general population, ALL survivors reported similar or higher HRQOL scores on all scales. Survivors with a relapse scored lower in general health perceptions (51.6) compared to those without (55.8;p=0.005), but after adjusting for self-reported late effects, this difference disappeared., Conclusion/significance: Compared to population norms, ALL survivors reported good HRQOL, even after a relapse. However, relapsed ALL survivors reported poorer general health than non-relapsed. Therefore, we encourage specialists to screen for poor general health in survivors after a relapse and, when appropriate, specifically seek and treat underlying late effects. This will help to improve patients' HRQOL.

The paired-box transcription factor Pax2 plays a major role in early development of the kidney and the central nervous system. It is expressed in the metanephric mesenchyme of the developing kidney, at the midbrain-hindbrain boundary and the anlagen of the inner ear. The early expression of Pax2, especially in the developing kidney, prompted us to use this locus as a novel genetic tool to introduce temporally-controlled expression of transgenes. We generated a transgenic Pax2-rtTA mouse strain through genetic recombineering using a large BAC clone which drives expression of TetO-controlled transgenes upon doxycycline treatment in natively Pax2-expressing tissues. We show that expression of a TetO-responsive lacZ gene is tightly regulated by addition of doxycycline and can be detected in all Pax2-expressing tissues. Our transgenic Pax2-rtTA mouse thus represents a suitable tool to study the cell fates and molecular pathways in Pax2-positive tissues during development, such as the kidney. We further propose that the Pax2-rtTA tool has great potential to induce time-controlled, tissue-specific alterations for tumorigenic transformation of Pax2-expressing cells for generating in vivo tumor models, such as Wilms tumor., (Copyright © 2011 Wiley-Liss, Inc.)

Clonal evolution of the leukemogenic compartment may contribute to alter the therapeutic response in acute lymphoblastic leukemia (ALL). Using xenotransplantation of primary leukemia cells, we evaluated the phenotypic and genetic composition of de novo resistant very high risk precursor B-cell ALL, a subgroup defined by the persistence of minimal residual disease despite intensive chemotherapy. Analysis of copy number alterations (CNAs) showed that the xenografted leukemia, even when reconstituted from 100 cells, remained highly related to the diagnostic sample, with minor changes in CNAs, mostly deletions, emerging in most cases in the first passage into mice. At the single-cell level, the pattern of monoallelic and biallelic deletions of the CDKN2A locus revealed distinct leukemia subpopulations, which were reproducibly tracked in xenografts. In most very high risk ALL cases, the predominant diagnostic clones were reconstituted in xenografts, as shown by multiplex polymerase chain reaction analysis of immunoglobulin and T-cell receptor loci. In other cases, the pattern in CNAs and immunoglobulin and T-cell receptor rearrangement was less concordant in xenografts, suggesting the outgrowth of subclones. These results unequivocally demonstrate the existence of clonally closely related but distinct subsets of leukemia initiating cells in ALL, which has important implications for drug development and preclinical disease modeling.

Study Aim: To develop a score predicting the risk of bacteremia in cancer patients with fever and neutropenia (FN), and to evaluate its performance., Methods: Pediatric patients with cancer presenting with FN induced by nonmyeloablative chemotherapy were observed in a prospective multicenter study. A score predicting the risk of bacteremia was developed from a multivariate mixed logistic regression model. Its cross-validated predictive performance was compared with that of published risk prediction rules., Results: Bacteremia was reported in 67 (16%) of 423 FN episodes. In 34 episodes (8%), bacteremia became known only after reassessment after 8 to 24 hours of inpatient management. Predicting bacteremia at reassessment was better than prediction at presentation with FN. A differential leukocyte count did not increase the predictive performance. The reassessment score predicting future bacteremia in 390 episodes without known bacteremia used the following 4 variables: hemoglobin ≥ 90 g/L at presentation (weight 3), platelet count <50 G/L (3), shaking chills (5), and other need for inpatient treatment or observation according to the treating physician (3). Applying a threshold ≥ 3, the score--simplified into a low-risk checklist--predicted bacteremia with 100% sensitivity, with 54 episodes (13%) classified as low-risk, and a specificity of 15%., Conclusions: This reassessment score, simplified into a low-risk checklist of 4 routinely accessible characteristics, identifies pediatric patients with FN at risk for bacteremia. It has the potential to contribute to the reduction of use of antimicrobials in, and to shorten the length of hospital stays of pediatric patients with cancer and FN.

Cancer stem cells (CSCs) have been identified in a number of solid tumors, but not yet in rhabdomyosarcoma (RMS), the most frequently occurring soft tissue tumor in childhood. Hence, the aim of this study was to identify and characterize a CSC population in RMS using a functional approach. We found that embryonal rhabdomyosarcoma (eRMS) cell lines can form rhabdomyosarcoma spheres (short rhabdospheres) in stem cell medium containing defined growth factors over several passages. Using an orthotopic xenograft model, we demonstrate that a 100 fold less sphere cells result in faster tumor growth compared to the adherent population suggesting that CSCs were enriched in the sphere population. Furthermore, stem cell genes such as oct4, nanog, c-myc, pax3 and sox2 are significantly upregulated in rhabdospheres which can be differentiated into multiple lineages such as adipocytes, myocytes and neuronal cells. Surprisingly, gene expression profiles indicate that rhabdospheres show more similarities with neuronal than with hematopoietic or mesenchymal stem cells. Analysis of these profiles identified the known CSC marker CD133 as one of the genes upregulated in rhabdospheres, both on RNA and protein levels. CD133(+) sorted cells were subsequently shown to be more tumorigenic and more resistant to commonly used chemotherapeutics. Using a tissue microarray (TMA) of eRMS patients, we found that high expression of CD133 correlates with poor overall survival. Hence, CD133 could be a prognostic marker for eRMS. These experiments indicate that a CD133(+) CSC population can be enriched from eRMS which might help to develop novel targeted therapies against this pediatric tumor.

In the Swiss Childhood Cancer Survivor Study, we aimed to assess the proportion of long-term survivors attending follow-up care, to characterise attendees and to describe the health professionals involved. We sent a questionnaire to 1252 patients, of whom 985 (79%) responded, aged in average 27 years (range 20-49). Overall, 183 (19%) reported regular, 405 (41%) irregular and 394 (40%) no follow-up. For 344, severity of late effects had been classified in a previous medical examination. Only 17% and 32% of survivors with moderate and severe late effects respectively had made regular visits a decade later. Female gender, after a shorter time since diagnosis, had radiotherapy, and having suffered a relapse predicted follow-up. In the past year, 8% had seen a general practitioner only, 10% a paediatric or adult oncologist and 16% other health specialists for a cancer related problem. These findings underline the necessity to implement tailored national follow-up programmes., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

A number of drugs developed against cancer-specific molecular targets have been shown to offer survival benefits alone or in combination with standard treatments, especially for those cases in which tumor pathogenesis is dominated by a single molecular abnormality. One example for such a tumor type is alveolar rhabdomyosarcoma (aRMS), which is characterized by a specific translocation creating the oncogenic PAX3/FKHR transcription factor, believed to be the molecular basis of the disease. Recently, we were able to show that the small molecule inhibitor PKC412 (midostaurin) shows strong antitumor activity against aRMS by reducing the transcriptional activity of PAX3/FKHR. In this study, we screened for combination strategies that are superior to PKC412-only treatment and found that the combination of PKC412 with histone deacetylase inhibitors like valproic acid (VPA) synergistically induced apoptosis resulting in suppressed aRMS tumor growth in vivo. We provide evidence that the antitumor effect on combination treatment is achieved by VPA-induced reactivation of p21, which is downregulated in aRMS cells by destabilization of the transcriptional regulator EGR1 by PAX3/FKHR. Our study highlights a possible mechanism behind the increased efficacy and indicates that different arms of PAX3/FKHR oncogenicity can be exploited therapeutically by the specific combination of drugs to increase their therapeutic potential.

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children. Improvement of treatment efficacy and decreased side effects through tumor-targeted drug delivery would be desirable. By panning with a phage-displayed cyclic random peptide library we selected a peptide with strong affinity for RMS in vitro and in vivo. The peptide minimal binding motif Arg-X-(Arg/Lys)(Arg/Lys) identified by alanine-scan, suggested the target receptor to be a proprotein convertase (PC). Expression profiling of all PCs in RMS biopsies and cell lines revealed consistent high expression levels for the membrane-bound furin and PC7. Direct binding of RMS-P3 peptide to furin was demonstrated by affinity chromatography and supported by activity and colocalization studies. Treatment of RMS in mice with doxorubicin coupled to the targeting peptide resulted in a two-fold increase in therapeutic efficacy compared to doxorubicin treatment alone. Our findings indicate surface-furin binding as novel mechanism for therapeutic cell penetration which needs to be further investigated. Furthermore, this work demonstrates that specific targeting of membrane-bound furin in tumors is possible for and suggests that RMS and other tumors might benefit from proprotein convertases targeted drug delivery.

PURPOSE To develop a score predicting the risk of adverse events (AEs) in pediatric patients with cancer who experience fever and neutropenia (FN) and to evaluate its performance. PATIENTS AND METHODS Pediatric patients with cancer presenting with FN induced by nonmyeloablative chemotherapy were observed in a prospective multicenter study. A score predicting the risk of future AEs (ie, serious medical complication, microbiologically defined infection, radiologically confirmed pneumonia) was developed from a multivariate mixed logistic regression model. Its cross-validated predictive performance was compared with that of published risk prediction rules. Results An AE was reported in 122 (29%) of 423 FN episodes. In 57 episodes (13%), the first AE was known only after reassessment after 8 to 24 hours of inpatient management. Predicting AE at reassessment was better than prediction at presentation with FN. A differential leukocyte count did not increase the predictive performance. The score predicting future AE in 358 episodes without known AE at reassessment used the following four variables: preceding chemotherapy more intensive than acute lymphoblastic leukemia maintenance (weight = 4), hemoglobin > or = 90 g/L (weight = 5), leukocyte count less than 0.3 G/L (weight = 3), and platelet count less than 50 G/L (weight = 3). A score (sum of weights) > or = 9 predicted future AEs. The cross-validated performance of this score exceeded the performance of published risk prediction rules. At an overall sensitivity of 92%, 35% of the episodes were classified as low risk, with a specificity of 45% and a negative predictive value of 93%. CONCLUSION This score, based on four routinely accessible characteristics, accurately identifies pediatric patients with cancer with FN at risk for AEs after reassessment.

In vivo resistance to first-line chemotherapy, including to glucocorticoids, is a strong predictor of poor outcome in children with acute lymphoblastic leukemia (ALL). Modulation of cell death regulators represents an attractive strategy for subverting such drug resistance. Here we report complete resensitization of multidrug-resistant childhood ALL cells to glucocorticoids and other cytotoxic agents with subcytotoxic concentrations of obatoclax, a putative antagonist of BCL-2 family members. The reversal of glucocorticoid resistance occurred through rapid activation of autophagy-dependent necroptosis, which bypassed the block in mitochondrial apoptosis. This effect was associated with dissociation of the autophagy inducer beclin-1 from the antiapoptotic BCL-2 family member myeloid cell leukemia sequence 1 (MCL-1) and with a marked decrease in mammalian target of rapamycin (mTOR) activity. Consistent with a protective role for mTOR in glucocorticoid resistance in childhood ALL, combination of rapamycin with the glucocorticoid dexamethasone triggered autophagy-dependent cell death, with characteristic features of necroptosis. Execution of cell death, but not induction of autophagy, was strictly dependent on expression of receptor-interacting protein (RIP-1) kinase and cylindromatosis (turban tumor syndrome) (CYLD), two key regulators of necroptosis. Accordingly, both inhibition of RIP-1 and interference with CYLD restored glucocorticoid resistance completely. Together with evidence for a chemosensitizing activity of obatoclax in vivo, our data provide a compelling rationale for clinical translation of this pharmacological approach into treatments for patients with refractory ALL.

The development of chemoresistance represents a major obstacle in the successful treatment of cancers such as neuroblastoma (NB), a particularly aggressive childhood solid tumour. The mechanisms underlying the chemoresistant phenotype in NB were addressed by gene expression profiling of two doxorubicin (DoxR)-resistant vs sensitive parental cell lines. Not surprisingly, the MDR1 gene was included in the identified upregulated genes, although the highest overexpressed transcript in both cell lines was the frizzled-1 Wnt receptor (FZD1) gene, an essential component of the Wnt/beta-catenin pathway. FZD1 upregulation in resistant variants was shown to mediate sustained activation of the Wnt/beta-catenin pathway as revealed by nuclear beta-catenin translocation and target genes transactivation. Interestingly, specific micro-adapted short hairpin RNA (shRNAmir)-mediated FZD1 silencing induced parallel strong decrease in the expression of MDR1, another beta-catenin target gene, revealing a complex, Wnt/beta-catenin-mediated implication of FZD1 in chemoresistance. The significant restoration of drug sensitivity in FZD1-silenced cells confirmed the FZD1-associated chemoresistance. RNA samples from 21 patient tumours (diagnosis and postchemotherapy), showed a highly significant FZD1 and/or MDR1 overexpression after treatment, underlining a role for FZD1-mediated Wnt/beta-catenin pathway in clinical chemoresistance. Our data represent the first implication of the Wnt/beta-catenin pathway in NB chemoresistance and identify potential new targets to treat aggressive and resistant NB.

Aims: Subclassification of rhabdomyosarcoma (RMS) has clinical relevance, as the two major subclasses embryonal (ERMS) and alveolar (ARMS) rhabdomyosarcoma differ greatly in terms of aggressiveness and prognosis. However, histological analysis is not always sufficient for an unequivocal subclassification of RMS. Furthermore, clinical presentation of ARMS has been reported to mimic other tumour types, specifically lymphoma. The aim was to determine the role of four biomarkers in the diagnosis of rhabdomyosarcoma., Methods and Results: Recently, we identified four potential biomarkers to subclassify RMS with high sensitivity and specificity. These included epidermal growth factor receptor (EGFR) and fibrillin-2 as markers for ERMS, and AP2beta and P-cadherin as markers for translocation-positive ARMS. Here, we further validate the potential of these four markers in a second, independent patient cohort by immunohistochemistry on 80 sections of RMS biopsy specimens as well as a tissue microarray representing 18 different additional tumour types, including seven lymphomas. The combination of EGFR and fibrillin-2 was able to detect ERMS with a specificity of 76% and sensitivity of 90%. The combination of AP2beta and P-cadherin detected ARMS with a specificity of 97% and sensitivity of 90%, data very similar to our previous study. Furthermore, all lymphomas were clearly negative for AP2beta and P-cadherin., Conclusions: These four biomarkers are suitable for clinical implementation in the future diagnosis of RMS.

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma in children. To improve existing therapies and broaden the spectrum of cytotoxic agents that can be used in RMS treatment, we performed a phage-display-based screening for peptides that bind specifically to RMS cells. Two peptides binding to RMS and to other tumour cell lines, but not to normal skeletal muscle cells and fibroblasts, were isolated from phage-displayed random peptide libraries. One peptide, named RMS-I (CQQSNRGDRKRC) contained the integrin-binding motif RGD and its binding was blocked by an antibody against alpha(v)beta(3)integrin, which is expressed on the RMS cell line RD. The isolation of RMS-I confirmed the validity of our screening procedure. The second peptide, named RMS-II (CMGNKRSAKRPC), shows sequence similarity to a previously identified peptide with tumour lymphatic specificity, LyP-1. However, RMS-II binds in vivo to RMS xenografts better than LyP-1 and homes to the tumour blood and not to lymphatic vessels. Therefore, RMS-II represents a promising peptide for the development of RMS-specific targeting approaches., ((c) 2008 Wiley-Liss, Inc.)

Karyotype analysis of acute lymphoblastic leukemia (ALL) at diagnosis has provided valuable prognostic markers for treatment stratification. However, reports of cytogenetic studies of relapsed ALL samples are limited. We compared the karyotypes from 436 nonselected B-cell precursor ALL patients at initial diagnosis and of 76 patients at first relapse. We noticed a relative increase of karyotypes that did not fall into the classic ALL cytogenetic subgroups (high hyperdiploidy, t(12;21), t(9;22), 11q23, t(1;19), <45 chromosomes) in a group of 29 patients at relapse (38%) compared to 130 patients at presentation (30%). Non-classical cytogenetic aberrations in these 29 patients were mostly found on chromosomes 1, 2, 7, 9, 13, 14, and 17. We also describe six rare reciprocal translocations, three of which involved 14q32. The most frequent abnormalities were found in 9p (12/29 cases) and were associated with a marked decrease in the duration of the second remission, but not of the probability of 10-year event-free survival after relapse treatment. From 29 patients with non-classical cytogenetic aberrations, only 8 (28%) had been stratified to a high risk-arm on the first treatment protocol, suggesting that this subgroup might benefit from the identification of new prognostic markers in future studies.

Background: Several studies have demonstrated that patients with childhood acute lymphoblastic leukemia presenting with mild anemia at diagnosis have an increased risk of poor outcome compared to patients with more severe anemia. However, it has not been reported whether there is any correlation between degree of anemia and leukemia subtype., Design and Methods: In a cohort of 1162 patients with childhood acute lymphoblastic leukemia we analyzed whether there was a correlation between degree of anemia and leukemia subtype. We also studied the association between degree of anemia and event-free survival within the subtypes., Results: Hemoglobin levels at diagnosis were distributed in a non-random pattern. The degree of anemia was significantly different for three distinct groups of patients compared to the remaining patients (mean hemoglobin; T-cell leukemia: 106 g/L versus 76 g/L (precursor B-cell acute lymphoblastic leukemia); within precursor B-cell ALL: TEL-AML1 positive: 68 g/L versus 79 g/L; BCR-ABL positive: 93 g/L versus 76 g/L; each p<0.05). Furthermore, in contrast to the entire study group, patients with T-cell leukemia, TEL-AML1(+), and BCR-ABL(+) precursor B-cell leukemia had a more favorable prognosis if presenting with a higher hemoglobin level (>/=80 g/L)., Conclusions: These observations indicate that the formerly reported direct correlation between severity of anemia and survival in childhood acute lymphoblastic leukemia mainly reflects differences in the degree of anemia between distinct biological subgroups with different treatment outcomes. On the other hand, the inverse relationship between severity of anemia and survival found within specific subgroups suggests that very low hemoglobin levels at diagnosis are associated with more advanced disease in these subgroups.

We describe a transgenic mouse line, Pax8-rtTA, which, under control of the mouse Pax8 promoter, directs high levels of expression of the reverse tetracycline-dependent transactivator (rtTA) to all proximal and distal tubules and the entire collecting duct system of both embryonic and adult kidneys. Using crosses of Pax8-rtTA mice with tetracycline-responsive c-MYC mice, we established a new, inducible model of polycystic kidney disease that can mimic adult onset and that shows progression to renal malignant disease. When targeting the expression of transforming growth factor beta-1 to the kidney, we avoided early lethality by discontinuous treatment and successfully established an inducible model of renal fibrosis. Finally, a conditional knockout of the gene encoding tuberous sclerosis complex-1 was achieved, which resulted in the early outgrowth of giant polycystic kidneys reminiscent of autosomal recessive polycystic kidney disease. These experiments establish Pax8-rtTA mice as a powerful tool for modeling renal diseases in transgenic mice.

Inhibition of constitutive active signaling pathways, which are a characteristic phenomenon for many tumors, can be an effective therapeutic strategy. In contrast, oncogenic transcription factors, often activated by mutational events, are in general less amenable to small-molecule inhibition despite their obvious importance as therapeutic targets. One example of this is alveolar rhabdomyosarcoma (aRMS), in which specific translocations lead to the formation of the chimeric transcription factor PAX3/FKHR. Here, we found unexpectedly that the transcriptional activity of PAX3/FKHR can be inhibited by the kinase inhibitor PKC412. This occurs via specific phosphorylation sites in the PAX3 domain, phosphorylation of which is required for efficient DNA-binding and subsequent transcriptional activity. Consequently, we show that PKC412 exerts a potent antitumorigenic potential for aRMS treatment both in vitro and in vivo. Our study suggests that posttranscriptional modifications of oncogenic transcription factors can be explored as a promising avenue for targeted cancer therapy.

Detection of minimal residual disease (MRD) is the most sensitive method to evaluate treatment response and one of the strongest predictors of outcome in childhood acute lymphoblastic leukemia (ALL). The 10-year update on the I-BFM-SG MRD study 91 demonstrates stable results (event-free survival), that is, standard risk group (MRD-SR) 93%, intermediate risk group (MRD-IR) 74%, and high risk group (MRD-HR) 16%. In multicenter trial AIEOP-BFM ALL 2000, patients were stratified by MRD detection using quantitative PCR after induction (TP1) and consolidation treatment (TP2). From 1 July 2000 to 31 October 2004, PCR target identification was performed in 3341 patients: 2365 (71%) patients had two or more sensitive targets (< or =10(-4)), 671 (20%) patients revealed only one sensitive target, 217 (6%) patients had targets with lower sensitivity, and 88 (3%) patients had no targets. MRD-based risk group assignment was feasible in 2594 (78%) patients: 40% were classified as MRD-SR (two sensitive targets, MRD negativity at both time points), 8% as MRD-HR (MRD > or =10(-3) at TP2), and 52% as MRD-IR. The remaining 823 patients were stratified according to clinical risk features: HR (n=108) and IR (n=715). In conclusion, MRD-PCR-based stratification using stringent criteria is feasible in almost 80% of patients in an international multicenter trial.

Despite embryonal rhabdomyosarcoma (eRMS) representing the most frequent form of RMS, the karyotypic characterization of this tumor subtype is still incomplete. We report the karyotypic analysis of two new cases of infant-onset eRMS. Both cases had a hyperdiploid karyotype, including gain of chromosomes 2 and 8. Only one of the cases showed a structural aberration, an unbalanced rearrangement involving 4p. These cases, together with a review of the literature, suggest that a karyotypic subgroup exists in infant eRMS that is defined by hyperdiploidy (<53 chromosomes) and includes gain of chromosomes 2, 8, 11, and 17, with few or no structural aberrations. Hence, this report illustrates that distinct karyotypic subgroups may be found in eRMS, which ultimately may be shown to have prognostic relevance.

The G-band cryptic t(12;21)(p13;q22) is the most common chromosomal rearrangement in childhood acute lymphoblastic leukemia (ALL). To investigate the nature of additional chromosomal events in this group of patients spectral karyotyping (SKY) following G-banding analysis was performed in 14 cases. From these cases six showed structural aberrations of chromosome 6, including both simple deletions and unbalanced translocations, and involved both q (n=4) and p (n=3) arms. The results show that rearrangements of 6p are also non-random events t(12;21)-positive ALL. This study illustrates the value of a combined SKY and G-banding approach in identifying novel karyotypic events in childhood ALL.

The chromosomal translocation t(2;13), characteristic for the aggressive childhood cancer alveolar rhabdomyosarcoma (aRMS), generates the chimeric transcription factor PAX3/FKHR with a well known oncogenic role. However, the molecular mechanisms mediating essential pathophysiological functions remain poorly defined. Here, we used comparative expression profiling of PAX3/FKHR silencing in vitro and PAX3/FKHR-specific gene signatures in vivo to identify physiologically important target genes. Hereby, 51 activated genes, both novel and known, were identified. We also found repression of skeletal muscle-specific genes suggesting that PAX3/FKHR blocks further differentiation of aRMS cells. Importantly, TFAP2B was validated as direct target gene mediating the anti-apoptotic function of PAX3/FKHR. Hence, we developed a pathophysiologically relevant transcriptional profile of PAX3/FKHR and identified a critical target gene for aRMS development.

Incorporation of apoptosis-inducing agents into current therapeutic regimens is an attractive strategy to improve treatment for drug-resistant leukemia. We tested the potential of arsenic trioxide (ATO) to restore the response to dexamethasone in glucocorticoid (GC)-resistant acute lymphoblastic leukemia (ALL). Low-dose ATO markedly increased in vitro GC sensitivity of ALL cells from T-cell and precursor B-cell ALL patients with poor in vivo response to prednisone. In GC-resistant cell lines, this effect was mediated, at least in part, by inhibition of Akt and affecting downstream Akt targets such as Bad, a proapoptotic Bcl-2 family member, and the X-linked inhibitor of apoptosis protein (XIAP). Combination of ATO and dexamethasone resulted in increased Bad and rapid down-regulation of XIAP, while levels of the antiapoptotic regulator Mcl-1 remained unchanged. Expression of dominant-active Akt, reduction of Bad expression by RNA interference, or overexpression of XIAP abrogated the sensitizing effect of ATO. The inhibitory effect of XIAP overexpression was reduced when the Akt phosphorylation site was mutated (XIAP-S87A). These data suggest that the combination of ATO and glucocorticoids could be advantageous in GC-resistant ALL and reveal additional targets for the evaluation of new antileukemic agents.

Primary infection with Epstein-Barr virus (EBV) is asymptomatic in children with immature immune systems but may manifest as infectious mononucleosis, a vigorous immune activation, in adolescents or adults with mature immune systems. Infectious mononucleosis and chronic immune activation are linked to increased risk for EBV-associated lymphoma. Here we show that EBV initiates progressive lytic infection by expression of BZLF-1 and the late lytic genes gp85 and gp350/220 in cord blood mononuclear cells (CBMC) but not in peripheral blood mononuclear cells (PBMC) from EBV-naive adults after EBV infection ex vivo. Lower levels of proinflammatory cytokines in CBMC, used to model a state of minimal immune activation and immature immunity, than in PBMC were associated with lytic EBV infection. Triggering the innate immunity specifically via Toll-like receptor-9 of B cells substantially suppressed BZLF-1 mRNA expression in acute EBV infection ex vivo and in anti-IgG-stimulated chronically latently EBV-infected Akata Burkitt lymphoma cells. This was mediated in part by IL-12 and IFN-gamma. These results identify immune activation as critical factor for the suppression of initiation of lytic EBV infection. We hypothesize that immune activation contributes to EBV-associated lymphomagenesis by suppressing lytic EBV and in turn promotes latent EBV with transformation potential.