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Background The study aimed to evaluate whether simplified chemotherapy followed by dose-reduced irradiation was effective for treating patients (ages 3–21 years) with localized germinoma. The primary endpoint was 3-year progression-free survival (PFS) rate. Methods Patients with a complete response to chemotherapy with carboplatin and etoposide received 18 Gy WVI + 12 Gy boost to the tumor bed. Patients with partial response proceeded to 24 Gy WVI + 12 Gy. Longitudinal cognitive functioning was evaluated prospectively on ALTE07C1 and was a primary study aim. Results One hundred and fifty-one patients were enrolled; 137 were eligible. Among 90 evaluable patients, 74 were treated with 18 Gy and 16 with 24 Gy WVI. The study failed to demonstrate noninferiority of the 18 Gy WVI regimen compared to the design threshold of 95% 3-year PFS rate, where, per design, patients who could not be assessed for progression at 3 years were counted as failures. The Kaplan-Meier (KM)-based 3-year PFS estimates were 94.5 ± 2.7% and 93.75 ± 6.1% for the 18 Gy and 24 Gy WVI cohorts, respectively. Collectively, estimated mean IQ and attention/concentration were within normal range. A lower mean attention score was observed at 9 months for patients treated with 24 Gy. Acute effects in processing speed were observed in the 18 Gy cohort at 9 months which improved at 30-month assessment. Conclusions While a failure according to the prospective statistical noninferiority design, this study demonstrated high rates of chemotherapy responses, favorable KM-based PFS and OS estimates in the context of reduced irradiation doses and holds promise for lower long-term morbidities for patients with germinoma.

Gliomas are the most common primary central nervous system tumors occurring in children and adults with neurofibromatosis type 1 (NF1). Over the past decade, discoveries of the molecular basis of low-grade gliomas (LGGs) have led to new approaches for diagnosis and treatments. However, these new understandings have not been fully applied to the management of NF1-associated gliomas. A consensus panel consisting of experts in NF1 and gliomas was convened to review the current molecular knowledge of NF1-associated low-grade “transformed” and high-grade gliomas; insights gained from mouse models of NF1-LGGs; challenges in diagnosing and treating older patients with NF1-associated gliomas; and advances in molecularly targeted treatment and potential immunologic treatment of these tumors. Next steps are recommended to advance the management and outcomes for NF1-associated gliomas.

ETMR, an aggressive disease characterised by C19MC alterations, were previously categorised as various histologic diagnoses. The clinical spectrum and impact of conventional multi-modal therapy on this new WHO diagnostic category remains poorly understood as a majority of ~200 cases reported to date lack molecular confirmation. We undertook comprehensive clinico-pathologic studies of a large molecularly confirmed cohort to improve disease recognition and treatment approaches. Amongst 623 CNS-PNETs patients enrolled in the RBTC registry, 159 primary ETMRs were confirmed based on a combination of FISH (125), methylation analysis (88), SNP and RNAseq (32) analyses; 91% had C19MC amplification/gains/fusions, 9% lacked C19MC alterations but had global methylation features of ETMR NOS. ETMRs arose in young patients (median age 26 months) predominantly as localized disease (M0-72%, M2-3 -18%) at multiple locations including cerebrum (60%) cerebellum (18%), midline structures (6%); notably 10% were brainstem primaries mimicking DIPG. Uni-and multivariate analyses of clinical and treatment details of curative regimens available for 110 patients identified metastatic disease (p=0.002), brainstem locations(p=0.005), extent of surgery, receipt of multi-modal therapy including high dose chemotherapy and radiation (P

BACKGROUND We report the outcomes of patients with pineoblastoma enrolled on the Head Start I-III trials. METHODS Twenty-three children were enrolled between 1991–2009. Treatment included maximal surgical resection followed by five cycles of intensive-chemotherapy and consolidation with marrow-ablative chemotherapy and autologous hematopoietic cell rescue (HDCx/AuHCR). Irradiation following consolidation was reserved for children over six years of age or those with residual tumor at the end of induction. RESULTS The median age was 3.12 years (range:0.44–5.72). Three patients withdrew from the protocols and two patients experienced chemotherapy-related mortality. Eight patients experienced progressive disease (PD) during induction chemotherapy. Ten patients received HDCx/AuHCR; eight experienced PD post-consolidation. Seven patients received craniospinal irradiation (CSI) with a median dose of 20.7 Gy (range:18–36 Gy) with boost(s) (median dose 27 Gy, range:18–36 Gy); three received CSI as adjuvant therapy (2 post-HDCx/AuHCR) and four upon progression/recurrence. The 5-year progression-free survival (PFS) and overall survival (OS) were 9.7% (95%,CI:2.6–36.0%) and 13% (95%,CI:4.5–37.5%), respectively. Three patients survived beyond five years. Nineteen patients relapsed in the following sites: local site (n=4), distal site (n=6), local and distal sites (n=9). Favorable OS prognostic factors were CSI (hazard ratio (HR)=0.30 (0.11–0.86), p=0.025), and HDCx/AuHCR (HR=0.40 (0.16–0.99), p=0.047). CONCLUSION CSI and HDCx/AuHCR were statistically associated with improved survival. The overall poor outcomes and high PD rate during later induction cycles and following consolidation chemotherapy warrants consideration of fewer induction cycles before consolidation and the intensification of consolidation with multiple cycles of marrow-ablative chemotherapy.

BACKGROUND Pineoblastoma (PB) is a rare but aggressive pediatric brain tumour arising from the pineal gland. Overall survival rates are estimated at 50–70%, with younger patients (< 5 years old) faring much worse (15–40%) despite intensive treatment regimens. Although germline RB1 and DICER1 alterations have been reported in a small proportion of PB, the clinical significance of such alterations and the biology of sporadic cases remains unknown. METHODS We collected tumor tissue from 93 PB cases diagnosed at their referring centres. We undertook global DNA methylation profiling and performed multiple orthogonal consensus clustering analyses to elucidate PB subgroups. Chromosomal copy number alterations were determined using Conumee and GISTIC2, and whole exome or targeted sequencing was completed. Clinical data was analyzed with correlative statistical methods and outcomes were measured by Kaplan-Meier survival estimates. RESULTS PB comprise five epigenetic groups, designated 1, 2, 3, 4A, and 4B. Deleterious, mutually exclusive alterations affecting miRNA biogenesis pathway members (DICER1, DROSHA, and DGCR8) were observed in 12/21 group 1 and 11/11 group 2 samples. Group 4A was characterized by recurrent RB1 loss and gain of the oncogenic miR-17/92, and group 4B by recurrent gain or amplification of MYC. These groups also exhibit distinct clinical features. PB groups 1–3 arose in older children (median ages 5.2–14.0 years) and had intermediate to excellent outcome (5-year OS of 71.9–100%). Group 4A and 4B were restricted to much younger children (median age 1.3–1.4 years) and had dismal prognoses (5-year OS 37.5% and 28.6%, respectively). CONCLUSIONS PB divides into five groups with distinct genetic and clinical profiles. These findings will have important implications for precise patient stratification and form the foundation for preclinical studies of biology-informed therapies.

BACKGROUND: Pediatric low-grade glioma (pLGG) is the most common CNS tumor of childhood. Progression-free survival (PFS) is much lower than overall survival emphasizing the need for alternative treatments. In addition, many children suffer functional morbidities such as visual and motor disturbances. Recently, there has been an appropriate prioritization of functional outcomes in children with pLGG. METHODS: We present the results of a PBTC phase II trial evaluating selumetinib, (AZD6244, ARRY-142886) a MEK-1/2 inhibitor, in children with recurrent/progressive pLGG on 2 strata, including visual outcomes. RESULTS: Stratum 3 enrolled Neurofibromatosis type 1 (NF1)-associated pLGG. Ten of 25 (40%) eligible patients had partial response (PR), 14/25 (56%) had stable disease (SD) and 1/25 (4%) had progressive disease (PD); 2-year PFS was 96+4%. Ten patients with optic pathway glioma (OPG) were evaluable for visual acuity (VA) at baseline and 1 year. VA improved in 2/10 patients (20%) and was stable in 8/10 (80%). One patient (10%) had improvement in visual fields (VF) and 9 patients (90%) had stable VF. Stratum 4 included patients with non-NF1-associated recurrent/progressive hypothalamic and OPG. Five of 25 (20%) eligible patients had PR, 16/25 (64%) had SD and 4 (16%) had PD; 2-year PFS was 78+8.5%. Nineteen of 25 patients were evaluable for VA. VA improved in 4/19 patients (21%), was stable in 13/19 (68%) and worsened in 2/19 (11%). Five patients (26%) had improved VF and 14 (74%) had stable VF. The most common toxicities included grade 1/2 CPK elevation, diarrhea, hypoalbuminemia and rash. Rare grade 3 toxicities included elevated CPK, rash and paronychia. CONCLUSIONS: Selumetinib was tolerable and effective in treating children with NF1-associated and sporadic recurrent/progressive hypothalamic and OPG based upon radiographic response and PFS. Twenty-seven of 29 (93%) evaluable patients had stable or improved vision based on VA and VF testing.

ACNS1123 was a Children’s Oncology Group Phase 2 study that was undertaken to determine whether irradiation could be safely reduced without impacting survival in a subgroup of NGGCT patients. Between May 2012-Jan 2017, 107 eligible patients were accrued to Stratum 1 (NGGCT stratum). Sixty-six (61.7%) patients achieved a complete/partial response (CR/PR) to induction chemotherapy and received 30.6Gy whole ventricular field irradiation followed by 54Gy tumor-bed boost achieving a 2-year progression-free survival rate of 89% (95% CI:81%-97%) and overall survival rate of 92% (95% CI:86%- 99%). Eight patients progressed; 6 had a spinal relapse and 2 patients had a local plus spinal relapse. Seven of eight patients had marker elevation at relapse and data was not available in one patient. At diagnosis, location was pineal in six cases, suprasellar in one, and bifocal in one case. Four patients had beta HCGβ and AFP elevation and two each had HCGβ and AFP elevation alone at diagnosis. Only two patients had HCGβ or AFP >1000 (HCGβ 3550 in one patient and AFP of 1340 in another). All eight patients were CR by markers; four had radiographic CR and four had a PR. Five patients had surgery at diagnosis: two had embryonal carcinoma, one germinoma, and two mixed germ cell tumor with malignant elements on histology. A consistent significant risk factor could not be identified to explain excess of spinal failures seen in our cohort.

BACKGROUND COG ACNS 1123 tested reduced radiotherapy (RT) for non-metastatic, non-germinomatous germ cell tumor (NGGCT) patients. The impact of central review on quality of RT and pattern of failure for NGGCT patients is evaluated. METHODS Patients who achieved a complete response (CR) or partial response (PR) to induction chemotherapy were eligible for reduced dose and field RT of 30.6 Gy whole ventricular field (WVI) and 54 Gy tumor-bed total dose. An online contouring atlas was available. Within three days of RT start, WVI plans were submitted for rapid central review. Within one week of RT completion, the complete RT record was submitted. Brain and spine MRIs of relapsed patients were centrally reviewed. RESULTS Between 5/2012–9/2016, 107 eligible patients were accrued and 70 met reduced RT criteria. Rapid RT review was performed for 49 (70%) of 70 patients. Forty-four (89.8%) required no modification. All modifications were completed and plans became compliant. Final central review was performed for 66 evaluable patients: 62 (94%) were per protocol; there were 2 major (1 dose and 1 target) and 2 minor deviations. Eight patients progressed; none had deviations. Median time to progression was 3.54 months (range: 1.7–19.1) from RT start. All failures had a spine component; two also had cranial component: one local progression (within the RT boost volume) and one leptomeningeal disease. CONCLUSION Providing an online contouring atlas and performing a rapid central review lead to high quality radiotherapy on this prospective trial. The deviations did not contribute to the pattern of failure.

INTRODUCTION Pediatric low-grade gliomas (pLGG) show clinical and biological features that are distinct from their adult counterparts. Consequently, additional considerations are needed for response assessment in children compared to the established adult Response Assessment in Neuro-Oncology (RANO) criteria. Standardized response criteria in pediatric clinical trials are lacking, complicating comparisons of responses across studies. We therefore established an international committee of the Radiologic Assessment in Pediatric Neuro-Oncology (RAPNO) working group to develop consensus recommendations for response assessment in pLGG. METHODS The committee consisted of 25 international experts in the areas of Pediatric Neuro-Oncology, Neuroradiology and Neurosurgery. The committee first developed a set of agreed upon topics they deemed necessary to understand the controversies of imaging utilization and assessment in pLGG. These topics were divided up among the committee members who presented all available literature to the entire RAPNO committee via web teleconference. Once presented, the group discussed these data and developed consensus statements and recommendations based on available literature, committee expertise and clinical experience. Each topic was discussed until a consensus was reached. RESULTS Final consensus included recommendations about the following topics: specific imaging sequences, advanced imaging techniques, NF1-associated pLGG, molecular and histologic classification, assessment of cysts, vision and other functional outcomes as well as overall radiologic response assessment. CONCLUSIONS The RAPNO pLGG consensus establishes systemic recommendations that represent an initial effort to uniformly collect and assess response in pLGG. These recommendations should now be evaluated internationally and prospectively in an effort to assess clinical utility, validate and modify as appropriate.

BACKGROUND CD40 is a co-stimulatory molecule expressed on antigen presenting cells (APCs). APX005M is a CD40 agonist monoclonal antibody which stimulates innate and adaptive anti-tumor immunity through activation of APCs, macrophages, and antigen-specific CD8+T-cells. Pediatric Brain Tumor Consortium study PBTC-051 is the first investigation of APX005M in pediatric patients and is evaluating the safety, recommended phase 2 dose (RP2D), pharmacokinetics, and preliminary efficacy of APX005M in children with central nervous system (CNS) tumors. RESULTS Accrual of patients with recurrent/refractory primary malignant CNS tumors (stratum 1) began in March 2018. 16 patients (2 ineligible) have enrolled on this stratum; 14 were treated. Dose escalation through 3 planned dose levels of APX005M was completed without excessive or unanticipated toxicities. The highest dose level (0.6 mg/kg q3 weeks) is the presumptive RP2D, and an expansion cohort is currently enrolling at this dose. 2 patients at dose level 3 have received >12 cycles of therapy. Grade 3 or higher adverse events at least possibly attributable to APX005M include 11 lymphopenia, 5 neutropenia, 5 leukopenia, 3 ALT elevations, 1 AST elevation, 1 thrombocytopenia, and 1 hypoalbuminemia. PK data will be available March 2020. Stratum 2 is now enrolling patients with post-radiation/pre-progression DIPG beginning at dose level 2, with 1 patient currently enrolled. CONCLUSION The CD40 agonistic antibody APX005M has demonstrated preliminary safety in pediatric patients with recurrent/refractory primary malignant CNS tumors and has a likely RP2D of 0.6 mg/kg q3 weeks in this population. Preliminary efficacy data are pending.

BACKGROUND: Pineoblastoma is a rare malignant pineal region tumor, the optimal management of which in young children remains unclear. METHODS: We report the outcomes of 23 children with pineoblastoma prospectively enrolled on three sequential Head Start (HS) trials between 1990 and 2009. The HS treatment strategy included maximal surgical resection followed by five cycles of intensive induction chemotherapy and consolidation with marrow-ablative chemotherapy and autologous hematopoietic cell rescue (HDCx/AuHCR). Irradiation following recovery from consolidation was reserved for children over six years old or with residual tumor. RESULTS: Data on 23 children with pineoblastoma including two with trilateral retinoblastoma aged 0.44–5.72 (median 3.12) years were analyzed. Median overall survival (OS) was 12 months (95% CI: 7.6–29.7 months). The 3-year progression-free survival (PFS) and OS were 14.5% (95% CI: 5.1–41.2%) and 17.4% (95% CI: 7.1–42.4%), respectively. Three patients were long-term survivors beyond 5 years. Eight patients experienced progressive disease (PD) during induction chemotherapy, six following the fourth and fifth cycles. Ten patients proceeded to consolidation with HDCx/AuHCR; eight experienced PD post-consolidation. Seven patients received craniospinal irradiation with boost(s) (median dose 20.7 (18–36) Gy), three patients as adjuvant therapy and four upon progression/recurrence. Favorable prognostic factors were administration of radiotherapy (hazard ratio (HR) for OS=0.30 (0.11–0.86), p

INTRODUCTION: Focal radiation therapy has long been and remains the only treatment option for diffuse intrinsic pontine glioma (DIPG). However, all patients show evidence of disease progression within months of completing radiation therapy (RT). Since chemotherapy does not provide significant outcome improvement, it is crucial to find a suitable radiosensitizer. Our research has shown that the JMJD3 demethylase inhibitor, GSK-J4, exerts potent anti-tumor activity on DIPG cells while restoring methylation. Our aim is to We hypothesized that GSK-J4 may inhibit radiation-induced DNA repair, making it a potential radiosensitizer. METHODS: RNA sequencing (RNA-Seq) was used to analyze gene expression changes by GSK-J4 in DIPG cells. ATAC-seq was conducted to determine chromatin accessibility in DIPG cells treated with GSK-J4. We evaluated DNA damage repair using DNA repair assay and immunocytochemistry of DSB markers γH2AX and 53BP1. Western blotting and quantitative PCR (qPCR) were conducted to evaluate differential expression of mRNA and proteins involved in DNA DSB repair. In vivo response to radiation monotherapy and combination of RT + GSK-J4 were measured by animal survival studies. RESULTS: RNA-Seq and qPCR show that GSK-J4 significantly reduces DNA DSB repair genes in DIPG cells. ATAC-seq results reveal that GSK-J4 modifies DNA accessibility to regulate expression of DNA repair genes. Immunocytochemistry results support that GSK- J4 sustains high levels of γH2AX and 53BP1 in irradiated DIPG cells, thereby inhibiting DNA DSB repair. DNA repair assay demonstrate that GSK-J4 inhibits DNA damage repair via the homologous recombination pathway. Western blotting revealed that GSK-J4 causes a sustained level of phosphorylated Rad50 and gH2AX in irradiated DIPG cells. In vivo studies revealed increased survival of animals treated with combination therapy compared to monotherapy. These results highlight GSK-J4 as a potential radiosensitizer in DIPG treatment.

Pineoblastoma (PB) is a rare but aggressive pediatric brain tumour arising from the pineal gland. Outcomes remain dismal with long-term survival rates between 10–40% despite intensive treatment regimens. Although germline RB1 and DICER1 alterations have been reported in a small proportion of PB, the clinical significance of such alterations and the biology of sporadic cases remains unknown. We undertook global methylation profiling of 75 PB cases, and discovered that PBs comprise four molecular sub-types, designated groups 1 to 4 with characteristic copy number alterations and mutational patterns. Molecular sub-groups of PB also exhibited distinct clinical features and survival outcomes. While PBs group 1–3 arose in older children (median ages 5.2–12.6 years), group 4 PB was restricted to much younger children (median age 1.4 years). Group 4 PB exhibited the highest incidence of metastases (53%) and had the worst 5-year event-free survival (EFS) and overall survival (OS), respectively 7.7% and 16.7%. In contrast, group 2 patients had a 5-year EFS and OS of 100%, while group 1 and 3 had intermediate outcomes (68.1%, 53.3% respectively). These findings demonstrate significant clinical and molecular heterogeneity in PB and underscore the critical need to define mechanisms underlying PB, so that precise patient stratification and selection of biology-informed therapies can be undertaken in future clinical trials.

The PBTC is conducting a phase II study (NCT01089101) evaluating selumetinib (AZD6244, ARRY-142886), a MEK I/II inhibitor, in children with recurrent/refractory LGG assigned to 6 strata. We present the updated data on Stratum 2 and 5. Also, data on subsequent progression after treatment completion in patients enrolled on Stratum 1 and 3 will be discussed. Finally, we present details on the re-treatment study (PBTC-029C). Both stratum 2 (pilocytic astrocytoma [PA] without common BRAF aberrations) and Stratum 5 (non-pilocytic LGG with BRAF aberrations) met response criteria for expansion (> 2 objective responses in 16 patients), and accrual to a total of 25 patients on each stratum is ongoing. Among 50 patients treated on Stratum 1 (PA with BRAF aberrations) or Stratum 3 (NF-associated LGG), 21 have progressed. Thirteen of 21 have progressed after stopping therapy. The median time to progression for these 13 patients is 119 days (10–928). The re-treatment study has enrolled 25 patients who received a median of 12 re-treatment courses (2–36). The most common attributable toxicities after re-treatment were grade 1 CPK elevation (44%), diarrhea (44%), hypoalbuminemia (40%), elevated AST (36%), rash (36%) and fatigue (32%). The most common grade 3/4 attributable toxicities were grade 3 paronychia (8%), CPK elevation (4%), AST elevation (4%), decreased ejection fraction (4%), neutropenia (4%), elevated triglycerides (4%), peripheral neuropathy (4%) and grade 4 CPK elevation (4%). There is not a significant difference between the toxicities observed during original therapy versus re-treatment. The most current response and patient demographic data will be presented.

Medulloblastoma (MB) is a malignant pediatric brain tumor characterized by poor neuronal differentiation. The RE1 Silencing Transcription Factor (REST), which negatively regulates neurogenesis by promoting repressive chromatin remodeling via epigenetic modifications, is overexpressed in human MBs. Analyses of a publically available gene expression array data set revealed association of elevated REST expression in patients with Sonic Hedgehog (SHH) medulloblastoma with poor prognosis. Upon closer evaluation, we identified a subset of highly undifferentiated SHHα tumors with elevated REST expression and activity as determined by expression of REST target genes. These patients had an overall survival rate of 50% at 5 years. To understand the underlying mechanisms, we generated a novel mouse model expressing human REST transgene in a conditional manner in granule neural progenitors (GNPs), the cells of origin of SHH driven MB. Mice with constitutive activation of Shh signaling and REST elevation (Ptch(+/-)/REST(TG)) in their GNPs developed tumors with a significant decrease in latency and increase in penetrance. We observed that 100% of Ptch(+/-)/REST(TG) animals developed heterogeneously proliferative and undifferentiated tumors compared to tumor-bearing Ptch(+/-) animals. Mechanistic studies revealed deregulation of the Shh signaling pathway by REST-dependent G9a activity, accompanied by loss of Ptch1 heterozygosity in Ptch(+/-)/REST(TG) tumors. Thus, our studies suggest that REST contributes to mis-regulation of SHH activity and drives an aggressive disease course by deregulating proliferation and differentiation. Ours is also the first study to implicate G9a, a repressive chromatin remodeler, in medulloblastoma pathogenesis and as a potential therapeutic target.

INTRODUCTION: Diffuse intrinsic pontine glioma (DIPG) remains a devastating and incurable disease. The DIPG-BATs clinical trial incorporates diagnostic biopsy with molecularly determined treatment stratification. Here we present the initial genomic analysis of the DIPG-BATs cohort. METHODS: Children enrolled on the DIPG-BATs clinical trial underwent upfront diagnostic biopsies prior to commencement of therapy. RNA and DNA were extracted from single core biopsies and subjected to whole-genome sequencing (WGS) and RNA-sequencing. Tumor samples were also collected at autopsy if there was parental consent. RESULTS: Fifty-three patients were enrolled on study, of whom 50 underwent biopsy. There were no biopsy-related deaths. A mean of 5ug of RNA and 10ug of DNA were extracted from single frozen cores. WGS on 41 DIPG samples (including eight autopsy samples) revealed a mean mutation rate of 0.753 mutations per Mb. We confirmed TP53, PIK3CA, H3F3A, ACVR1, PPM1D, and HIST1H3B to be recurrently mutated in DIPG. Additional mutations were found in epigenetic modifiers including ASXL1. Copy-number analysis revealed PDGFRA to meet statistical significance as a recurrent amplification peak in DIPG (q

INTRODUCTION: Focal radiation therapy has long been and still remains the only treatment option for diffuse intrinsic pontine glioma (DIPG). However, all children who suffer from this inoperable and uniformly fatal cancer show evidence of disease progression within months of completing radiation therapy, especially those who harbor the H3.3K27M mutation. Since chemotherapy does not provide any significant outcome improvement, it is crucial to find a suitable radiosensitizer. Our research has shown that the JMJD3 demethylase inhibitor, GSK-J4, not only exerts potent anti-tumor activity on H3K27M mutant DIPG cells, but also restores methylation while decreasing genes that encode proteins involved in DNA double-strand break (DSB) repair. Our aim is to investigate the hypothesis that GSK-J4 may inhibit radiation-induced DNA repair via chromatin modification, making it a potential radiosensitizing agent. METHODS: We evaluated DNA damage repair via quantitative-PCR (q-PCR), immunocytochemistry of DSB markers γH2AX and 53BP1, and DNA repair assay. MNase digestion was used to analyze nucleosome assembly in cellular chromatin. We are currently conducting western blotting, DNA repair assay, FAIRE-seq and clonogenic survival assays to assess DIPG response to radiation therapy (RT) in combination with GSK-J4. In vivo response to radiation monotherapy and combination of RT + GSK-J4 will be measured by bioluminescence imaging and animal survival studies. RESULTS: qPCR results showed that GSK-J4 significantly reduces DNA DSB repair genes such as PARP1, PARP2, SMARCB1 and BRCA1, in irradiated DIPG cells. Immunocytochemistry results support that GSK- J4 sustains high levels of γH2AX and 53BP1 in irradiated DIPG cells, thereby inhibiting DNA DSB repair. MNase assay indicated that GSK-J4 may cause chromatin compaction which prevents DNA DSB repair. Results from the clonogenic assays, to assess long term effect of GSK-J4 on radiated cells, as well as western blotting, FAIRE-seq and in vivo studies will be reported at the meeting.

Item does not contain fulltext Background.: Pineoblastoma is a rare pineal region brain tumor. Treatment strategies have reflected those for other malignant embryonal brain tumors. Patients and Methods.: Original prospective treatment and outcome data from international trial groups were pooled. Cox regression models were developed considering treatment elements as time-dependent covariates. Results.: Data on 135 patients with pineoblastoma aged 0.01-20.7 (median 4.9) years were analyzed. Median observation time was 7.3 years. Favorable prognostic factors were age >/=4 years (hazard ratio [HR] for progression-free survival [PFS] 0.270, P < .001) and administration of radiotherapy (HR for PFS 0.282, P < .001). Metastatic disease (HR for PFS 2.015, P = .006), but not postoperative residual tumor, was associated with unfavorable prognosis. In 57 patients /=4 years, PFS/OS were 72 +/- 7%/73 +/- 7% for patients without metastases, and 50 +/- 10%/55 +/- 10% with metastases. Seventy-three patients received radiotherapy (48 conventionally fractionated CSI, median dose 35.0 [18.0-45.0] Gy, 19 hyperfractionated CSI, 6 local radiotherapy), with (n = 68) or without (n = 6) chemotherapy. The treatment sequence had no impact; application of HDCT had weak impact on survival in older patients. Conclusion.: Survival is poor in young children treated without radiotherapy. In these patients, combination of HDCT and local radiotherapy may warrant further evaluation in the absence of more specific or targeted treatments. CSI combined with chemotherapy is effective for older non-metastatic patients.

A major goal of our work is to study medulloblastoma biology to facilitate the development of targeted therapy. Here, we have dissected the contribution of epigenetics to tumor development. Epigenetic perturbations are pharmacologically reversible and may have therapeutic potential. The RE1-Silencing Transcription Factor (REST) is an epigenetic modulator, and a repressor of neuronal differentiation genes. Its expression is significantly elevated in human medulloblastomas, and is associated with poor prognosis. REST is a driver of medulloblastoma in mouse orthotopic models. To understand REST's contribution to tumor development, we created a novel genetically engineered mouse model in which REST transgene is conditionally elevated in the cerebellar granule progenitors (GNPs), the cells of origin of some medulloblastoma. Transgene induction caused GNP hyperproliferation, accompanied by a failure to express the cell cycle regulator-p27. Using genetic and biochemical approaches, we attributed the lack of p27 expression to direct REST-mediated repression of a novel deubiquitylase, USP37. We also identified a role for USP37 in p27 protein stabilization, and terminal cell cycle exit. USP37 and p27 levels were significantly correlated in patient samples, and their loss was associated with poor overall patient survival. Importantly, constitutive USP37 expression blocked the tumorigenic potential of high-REST human medulloblastomas, suggesting a tumor suppressive function for USP37. REST binding to the USP37 promoter caused increased histone H3 lysine (K)-9 tri-methylation, an epigenetic mark associated with gene silencing. The histone methyl-transferase G9a, which promotes this modification, is a known REST co-repressor. Importantly, genetic ablation of G9a or pharmacological inhibition of its activity upregulated USP37 expression in a REST-dependent manner, and blocked tumor growth in mice. Our work has provided the first link between epigenetic deregulation of the proteasome and medulloblastoma development, and supports the manipulation of the REST-epigenome for future therapeutic application.

BACKGROUND: Recent progress in medulloblastoma biology has confirmed the presence of 4 clinically and molecularly distinct subgroups. MicroRNAs are dysregulated in cancer, including pediatric central nervous system tumors. We aim to determine if microRNA expression can aid in the molecular classification of medulloblastoma in tissue and cerebrospinal fluid (CSF). METHODS: RNA purification from 41 formalin-fixed paraffin embedded primary medulloblastoma samples was performed. TaqMan® miRNA assays were used to quantify the levels of 762 mature miRNAs from each sample using the Applied Biosystems 7900HT Fast Real-Time PCR system. Molecular subgrouping using established gene sets was performed using the Nanostring® platform. Clinical, pathologic and outcome data was collected on all patients. In a separate cohort of patients with medulloblastoma, expression of circulating miRNA was quantified in CSF at the time of diagnosis. RESULTS: Molecular subgrouping by gene expression classified tumors into WNT (n = 6), Shh (n = 5), Group 3 (n = 11) and Group 4 (n = 19) tumors. Clinical and outcome data was consistent with previously published cohorts. Consensus clustering by microRNA expression is not sufficient for molecular subgrouping. Independent of subgroup, the presence of metastatic disease at diagnosis was associated with high levels of miR-373 (p = 0.003) and miR-213 (p = 0.003) and expression of miR-497 was associated with poor overall survival (p =

BACKGROUND: Steroid induced toxicities adversely affect the quality of life of children treated with brain tumors. Side effects include; mood changes, myopathy, weight gain, fluid retention, hypertension, moon faces, acne, etc. Alternatives to control peritumoral edema are needed. METHODS: Eligible patients included Pediatric patients less than 18 years of age on chronic corticosteroids who failed attempts to wean. A two part trial consisting of a Phase I dose escalation phase followed by a long-term (26 week) maintenance phase was undertaken. Patients were initially enrolled at a dose of 10 ug/kg divided BID, and in the absence of DLTs, were escalated to 20 ug/kg/day, 30 ug/kg/day, 40 ug/ kg/day and 60ug/kg/day of Xereceptw. If no DLT's were observed in cohorts of 3 subjects, subsequent patients were started at the next highest dose level with a plan to assess twelve patients at the highest tolerated dose. The study was designed to evaluate: toxicities of Xerecept, dexamethasone dose reduction, changes in steroid induced side effects and HRQoL. Dexamethasone dose reduction was allowed beginning after 7 days of Xerecept. RESULTS: 15 subjects were enrolled, 14 evaluable patients with recurrent DIPG(8), HGG (4) and ependymoma (2) received Xerecept. No patients experienced a DLT. All evaluable patients were able able to reduce dexamethasone. From a mean starting dose of 5.4 mg/day to a minimal dose of 1 mg/day in 87.5% of patients on treatment for at least 6 weeks. 4 patients weaned off completely despite progressive disease. QOL analysis revealed significant improvements in physical functioning, emotional functioning, and improvements in sleep/rest and fatigue scores for all evaluable patients at week 18. CONCLUSIONS: Xerecept at 60 ug/kg/day is safe and well tolerated. Even in this poor prognosis population, significant dose reduction of corticosteroids can occur with Xerecept. Patient QOL improved as evident by changes in emotional, physical and fatigue scores. Future efficacy trials with Xerecept are warranted, a Phase II/III trial is planned. SECONDARY CATEGORY: Pediatrics.

Pediatric low-grade glioma (LGG) is a heterogeneous group of tumors constituting the most frequent CNS neoplasia encountered in this population. Pilocytic astrocytoma (PA) is the commonest LGG in children.1 Initial treatment of children with LGG (excluding the optic pathway and intrinsic brainstem lesions) is surgical resection and is often curative.2 Patients with recurrent LGG usually receive chemotherapy and/or focal radiotherapy.3,4 Cytotoxic treatment, especially radiotherapy, has the potential for causing serious long-term toxicities, especially in young children with a disease that can be chronic and compatible with prolonged survival.5,6 Also, patients with recurrent LGG who fail standard chemotherapy regimens and/or radiotherapy have few available treatment options, and novel therapies are urgently needed. Tumor angiogenesis is a process that is essential for tumor growth beyond a certain size and ultimately promotes tumor infiltration and metastasis.7 Vascular endothelial growth factor (VEGF) is a key angiogenesis mediator that is overexpressed in CNS tumors, including LGG.8–10 Bevacizumab (BVZ; Avastin, Genentech) is a humanized monoclonal antibody that is highly specific for all VEGF isoforms.11 In 2006, based on promising results from the use of BVZ + camptothecin (CPT)-11 in adults with recurrent malignant glioma, the Pediatric Brain Tumor Consortium (PBTC) initiated a phase II study in children with recurrent brain tumors, including malignant glioma, brainstem glioma, ependymoma, and medulloblastoma.12,13 In 2008, following encouraging results from a limited institution pilot study of the same combination in 10 patients with recurrent LGG, an additional stratum was added to assess the efficacy and toxicity of this regimen in this patient population.14,15 We now report on the efficacy of this combination in this stratum.

A phase II study of bevacizumab (BVZ) plus irinotecan (CPT-11) was conducted in cases of pediatric recurrent ependymoma (EPN) to estimate sustained objective response rate and progression-free survival (PFS). Eligible patients received 2 doses of single-agent BVZ intravenously (10 mg/kg) 2 weeks apart and then BVZ + CPT-11 every 2 weeks until progressive disease, unacceptable toxicity, or a maximum of 2 years of therapy. Correlative studies included diffusion-weighted and T1 dynamic contrast enhanced permeability imaging and tumor immunohistochemistry for vascular endothelial growth factor (VEGF)–A and –B, hypoxia inducible factor–2α, VEGF receptor (R)–2, and carbonic anhydrase (CA)–9. Thirteen evaluable patients received a median of 3 courses (range, 2–12) of BVZ + CPT-11. No sustained response was observed in any patient. Median time to progression in 10 patients was 2.2 months (range, 1.9–6.3). Two patients had stable disease for 10 months and 12 months, respectively. Six-month PFS was 25.7% (SE = 11.1%). Grades I–III toxicities related to BVZ treatment included fatigue in 4 patients, systemic hypertension in 2, epistaxis in 1, headache in 1, and avascular necrosis of bone in 1. Although there was a decrease in the mean diffusion ratio following 2 doses of BVZ, it did not correlate with PFS. BVZ + CPT-11 was well tolerated but had minimal efficacy in cases of recurrent EPN.