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Object: The incidence of ependymoma in patients with neurofibromatosis-2 (NF-2) is low and information regarding treatment and prognosis is lacking. We present two cases of cervicomedullary tumors in patients with NF-2 from our institution, and we provide a review of the literature in order to summarize the known clinical information about this rare occurrence. Patients and methods: Patient #1 had histological confirmation of ependymoma and was treated with subtotal resection followed by observation and has had no evidence of progression for 11 months. Patient #2 has been observed for 4 1/2 years without treatment for a cervicomedullary tumor, which appears to be an ependymoma by imaging. Although it has increased in size very slowly, there have been no clinical symptoms. Among the additional 21 cases of NF-2 and ependymoma from the literature, the most common location is the cervical spine (70%), and the median age at diagnosis is 15 years. Surgical resection was performed in 85% of the cases and subtotal resection in 64% of cases. Fifteen patients (75%) were reported alive at the time of the published reports, with survival ranging from 0.1 to 10 years, and the 8-year survival estimated as 51%. Survival was related to the location of the tumor. Conclusions: We conclude from our two cases and review of the existing literature that NF-2 associated spinal ependymomas have an indolent course and typically can be observed or treated by surgical excision alone. [ABSTRACT FROM AUTHOR]

We previously showed that inhibition of the platelet-derived growth factor receptor (PDGFR) blocks the survival and migration of medulloblastoma cells. Identification of in vitro PDGFR-targeting pharmacologic agents that are suitable for preclinical testing in medulloblastoma models in vivo will be critical for efficiently translating these agents to clinical investigation in children with medulloblastoma. In this study, we investigated whether the multi-tyrosine kinase inhibitor sunitinib, effectively inhibits PDGFR signaling required for medulloblastoma cell migration. Daoy and D556 human medulloblastoma cells pre-treated for 1 h with 0.2 μM sunitinib demonstrated induction of PTEN expression and significant inhibition of PDGFR signaling activity and transactivation of EGFR, in a RAS-independent manner, in response to PDGF-BB stimulation. Sunitinib pre-treatment markedly reduced medulloblastoma cell migration in response to both PDGF-BB and 10% serum at 4 and 24 h after treatment. Pre-treatment with sunitinib for 1 h also resulted in detachment and decreased viability of D556, but not Daoy, cells and only after 48 h following treatment. However, sunitinib did not induce apoptosis in either cell line at any time point, indicating that the anti-migratory effects of sunitinib were not due to impeding cell survival. Sunitinib similarly inhibited PDGFR signaling and migration of primary murine Smo/Smo medulloblastoma cells, suggesting that the Smo/Smo mouse is an appropriate model for preclinical testing of sunitinib. These results indicate that sunitinib may be an important pharmacologic agent for the treatment of invasive medulloblastoma, particularly given evidence of its ability to cross the blood-brain barrier to target tumor cells, and thus warrants further in vivo testing for confirmation of efficacy. [ABSTRACT FROM AUTHOR]

We previously identified that overexpression of the platelet-derived growth factor receptor (PDGFR) is associated with metastatic medulloblastoma (MB) and showed that PDGF treatment increases ERK activity and promotes MB cell migration. In this study, we investigated whether ERK regulates Rac1/Pak1 signaling and is critically linked to MB cell migration. Herein we demonstrate that PDGF-BB treatment of MB cells induces concomitant activation of PDGFRβ, MEK1/ERK, Rac1 and Pak1, but suppresses Rho activity, which together significantly promotes cell migration. Conversely, cells transfected with either PDGFRβ or Pak1 siRNA or treated with an inhibitor of Rac1 (NSC23766) or N-myristoyltransferase-1 (Tris-dipalladium) are unable to activate Rac1 or Pak1 in response to PDGF, and consequently, are unable to undergo PDGF-mediated cell migration. Furthermore, we also demonstrate that either chemical inhibition of MEK/ERK (U0126) or stable downregulation of PDGFRβ by shRNA similarly results in the loss of PDGF-induced ERK phosphorylation and abolishes Rac1/Pak1 activation and cell migration in response to PDGF. However, specific depletion of Pak1 by siRNA has no effect on PDGF-induced ERK phosphorylation, indicating that in MB cells ERK signaling is Pak1-independent, but PDGF-induced migration is dependent on ERK-mediated activation of Pak1. Finally, using tissue microarrays, we detect phosphorylated Pak1 in 53% of medulloblastomas and show that immunopositivity is associated with unfavorable outcome. We conclude that Rac1/Pak1 signaling is critical to MB cell migration and is functionally dependent on PDGFRβ/ERK activity. [ABSTRACT FROM AUTHOR]

The purpose is to determine the incidence of active and latent human herpesvirus-6 (HHV-6) infection in a large cohort of adult primary and recurrent CNS tumors. We screened a tissue microarray (TMA) containing more than 200 adult primary and recurrent CNS tumors with known clinical information for the presence of HHV-6 DNA by in situ hybridization (ISH) and protein by immunohistochemistry (IHC). One hundred six of 224 (47%) CNS tumors were positive for HHV-6 U57 Major Capsid Protein (MCP) gene by ISH compared to 0/25 non tumor control brain ( P = 0.001). Fourteen of 30 (47%) tumors were HHV-6 MCP positive by nested PCR compared to 0/25 non-tumor brain controls ( P = 0.001), revealing HHV-6 Variant A in 6 of 14 samples. HHV-6A/B early (p41) and late (gp116/64/54) antigens were detected by IHC in 66 of 277 (24%) ( P = 0.003) and 84 of 282 (35%) ( P = 0.002) tumors, respectively, suggesting active infection. HHV-6 p41 ( P = 0.645) and gp116/64/54 ( P = 0.198) antigen detection was independent of recurrent disease. Glial tumors were 3 times more positive by IHC compared to non glial tumors for both HHV-6 gp116/64/54 ( P = 0.0002) and HHV-6 p41 ( P = 0.004). Kaplan Meier survival analysis showed no effect of HHV-6 gp116/64/54 ( P = 0.852) or HHV-6 p41 ( P = 0.817) antigen detection on survival. HHV-6 early and late antigens are detected in adult primary and recurrent CNS tumors more frequently in glial tumors. We hypothesize that the glial-tropic features of HHV-6 may play an important modifying role in tumor biology that warrants further investigation. [ABSTRACT FROM AUTHOR]

Summary: Medulloblastoma is the most common embryonal tumour in children. Patients with medulloblastoma are currently staged as average-risk or poor-risk on the basis of clinical findings. With current multimodality therapy, nearly 90% of children with average-risk, non-disseminated medulloblastoma have 5-year event-free survival, and those with high-risk disease have a 60–65% survival rate; however, the outcome for younger children, particularly infants, is worse. Children who survive medulloblastoma are at risk of long-term sequelae related to the neurological effects of the tumour, surgery, or radiotherapy, and the additive effects of chemotherapy. Molecular biology has changed our understanding of medulloblastoma and has implications for diagnostic stratification and treatment. As newer biological agents are translated from the lab to the bedside, clinicians need to understand the fundamental signalling pathways that are targeted during therapy. Greater understanding of the molecular biology of medulloblastoma is needed so that more children can be cured or have an improved quality of life. [Copyright &y& Elsevier]

Background: Despite the use of surgery, radiotherapy (RT) and standard chemotherapy, childhood high-grade astrocytoma (HGA) continues to carry a dismal prognosis. In an attempt to identify effective drug combinations and an alternative treatment strategy, the Children's Cancer Group (CCG) conducted a nationwide clinical trial that prospectively evaluated 102 children with HGA and post-operative residual disease for efficacy and toxicity of four courses of high-dose chemotherapy (HDCT) before RT. Design and methods: Patients were randomly assigned to one of three couplets of drugs: carboplatin/etoposide (Regimen A); ifosfamide/etoposide (Regimen B); or cyclophosphamide/etoposide (Regimen C). After HDCT, all patients received local RT followed by lomustine and vincristine. Results: Of 76 evaluable patients (median age 11.95 years, range 3-20 years), 30 patients relapsed during HDCT and 11 others did not complete HDCT due to toxicity. Non-hematologic serious toxicities were common (29%) and 21% of patients did not receive RT. Objective response rates were not associated with amount of residual disease and did not statistically differ between regimens: 27% (Regimen A), 8% (Regimen B), and 29% (Regimen C). Overall survival (OS) was 24 ± 5% at 5 years and did not differ between groups. The 5-year, event-free survival (EFS) for all patients was 8 ± 3% and 14 ± 7% for Regimen A (p = 0.07). Patients who responded to HDCT had a nominally higher survival rate (p = 0.03 for trend). Interpretation: HDCT prior to RT provides no additional clinical benefit to conventional treatment in HGA, regardless of the amount of measurable residual tumor, and adversely effects ability to complete RT. Strong consideration should be given to investigating alternative strategies and novel biologic agents for this disease. [ABSTRACT FROM PUBLISHER]

For the past two decades, staging studies have been used to stratify children with medulloblastoma into risk groups. Therapeutic approaches have been based on separation of patients into ‘average-risk’ and ‘poor-risk’ categories. The extent of disease at diagnosis has been most reproducibly shown to be of prognostic significance, but age at diagnosis and amount of residual disease after surgery or extent of resection have also been commonly incorporated into stratification schemata. Tumor histology has been variably related to outcome. Biologic markers, especially molecular genetic findings, have not yet been incorporated into risk classifications, but will likely add to the understanding of medulloblastoma and may significantly alter concepts of staging and treatment.Copyright © 2003 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Metastasis is the leading cause of treatment failure in medulloblastoma. Understanding the genetic regulation of metastasis may aid in the development of novel treatments. We therefore performed in silico analysis of the mRNA expression of 83 medulloblastomas compiled from two independent microarray studies by focusing on 135 genes most frequently linked to metastasis in other tumors. We then asked whether expression of these genes correlated with metastasis in the medulloblastoma array data sets. We found the platelet-derived growth factor receptor alpha, early growth response protein 1 and insulin-like growth factor 2 genes as well as several genes associated with MYCC and ERBB2 overexpressed by at least 2-fold in metastatic tumors in both array data sets. We conclude that these genes may interact to promote prometastatic signaling in medulloblastoma.Copyright © 2003 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The plasminogen activation (PA) system plays an important role in tumor invasion by initiating pericellular proteolysis of the extracellular matrix (ECM) and inducing cell migration. Malignant brain tumors overexpress PA members and characteristically invade by migrating on ECM-producing white matter tracts and blood vessel walls. To determine whether urokinase-type plasminogen activator (uPA) and its receptor (uPAR) directly modulate the migration of brain tumor cells, we examined six human brain tumor cell lines, 2 astrocytomas (SW1088, SW1783), 2 medullobastomas (Daoy, D341Med), and 2 glioblastomas (U87MG, U118MG), for their surface uPAR expression, endogenous PA activity, and functional proteolytic activity by an ECM-degradation assay. Migration on Transwell membranes and invasion of Matrigel was then tested by pre-incubating the cells with increasing concentrations of either uPA, the proteolytically inactive amino-terminal fragment (ATF) of uPA, or the uPAR cleaving enzyme, phosphatidylinositol-specific phospholipase C (PI-PLC). All of the cell lines, except D341Med, express surface uPAR protein and uPA activity. High levels of uPAR and uPA activity correlated with cellular degradation of ECM, cell migration, and Matrigel invasion. Cell migration and invasion were enhanced by uPA or ATF in a dose dependent manner, while PI-PLC treatment abolished the uPA effect and inhibited migration and invasion. We conclude that ligation of uPAR by uPA directly induces brain tumor cell migration, independent of uPA-mediated proteolysis; and in concert with ECM degradation, markedly enhances invasion. Conversely, removing membrane bound uPAR from the surface of the cells studied inhibited their ability to migrate and invade even in the presence of proteolytically active uPA. [ABSTRACT FROM AUTHOR]

Simple Summary: Imipramine blue (IB) is a novel NADPH oxidase inhibitor. We assessed the single agent activity of IB against a well-established model of medulloblastoma, the most common malignant brain tumor of childhood. IB slowed progression of medulloblastoma and increased survival of mice with transgenic medulloblastoma. Clinical trials of IB for medulloblastoma should be pursued. Sonic hedgehog subtype of medulloblastoma (SHH MB) with metastasis or specific clinical or molecular alteration shas a poor prognosis and current therapy results in long-term cognitive impairment in the majority of survivors. Thus, a great need exists for new targeted therapeutic approaches to more effectively treat SHH MB in children. Imipramine blue (IB), a novel molecule with anti-tumor properties, inhibits the NADPH oxidase (NOX) family of enzymes, which are critical for SHH MB survival and treatment resistance. In this study, IB was encapsulated within a liposome to form a liposomal nanoparticle, Liposome-IB (Lipo-IB). This complex has the ability to cross the blood–brain barrier and be preferentially taken up by tumor cells within the brain. We demonstrated in vitro that Lipo-IB treatment caused a dose-dependent decrease in SHH MB cell viability and migration. Short-term administration of single agent Lipo-IB treatment of SHH MB in vivo significantly inhibited tumor growth, reduced the tumor volume, including a complete tumor response, and improved survival compared to control treated mice, without any observable toxicity. We conclude that Lipo-IB is a potential novel nanoparticle-based therapeutic for the treatment of SHH MB that warrants further preclinical safety and efficacy testing for development towards clinical investigation. [ABSTRACT FROM AUTHOR]

The original version of this article unfortunately contained a mistake. [ABSTRACT FROM AUTHOR]

Medulloblastoma, which is the most common malignant paediatric brain tumour, has a 70% survival rate, but standard treatments often lead to devastating life-long side effects and recurrence is fatal. One of the emerging strategies in the search for treatments is to determine the roles of tumour microenvironment cells in the growth and maintenance of tumours. The most attractive target is tumour-associated macrophages (TAMs), which are abundantly present in the Sonic Hedgehog (SHH) subgroup of medulloblastoma. Here, we report an unexpected beneficial role of TAMs in SHH medulloblastoma. In human patients, decreased macrophage number is correlated with significantly poorer outcome. We confirm macrophage anti-tumoural behaviour in both ex vivo and in vivo murine models of SHH medulloblastoma. Taken together, our findings suggest that macrophages play a positive role by impairing tumour growth in medulloblastoma, in contrast to the pro-tumoural role played by TAMs in glioblastoma, another common brain tumour. The Sonic Hedgehog subgroup of medulloblastoma are characterised by the high infiltration of tumour-associated macrophages (TAMs). Here, the authors show that TAM numbers in patients are associated with better prognosis and that, consistently, in a murine model of medulloblastoma, these TAMs have anti-tumoural properties. [ABSTRACT FROM AUTHOR]

Treatment for medulloblastoma (MB) — the most common malignant pediatric brain tumor — includes prophylactic radiation administered to the entire brain and spine due to the high incidence of metastasis to the central nervous system. However, the majority of long-term survivors are left with permanent and debilitating neurocognitive impairments as a result of this therapy, while the remaining 30-40% of patients relapse with terminal metastatic disease. Development of more effective targeted therapies has been hindered by our lack of understanding of the underlying mechanisms regulating the metastatic process in this disease. To understand the mechanism by which MB metastasis occurs, three-dimensional matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) experiments were performed on whole brains from a mouse model of human medulloblastoma. Analyzing the tumor and surrounding normal brain in its entirety enabled the detection of low abundance, spatially-heterogeneous lipids associated with tumor development. Boundaries of metastasizing and non-metastasizing primary tumors were readily defined, leading to the identification of lipids associated with medulloblastoma metastasis, including phosphatidic acids, phosphatidylethanolamines, phosphatidylserines, and phosphoinositides. These lipids provide a greater insight into the metastatic process and may ultimately lead to the discovery of biomarkers and novel targets for the diagnosis and treatment of metastasizing MB in humans. [ABSTRACT FROM AUTHOR]

Functions of the transcription factor REST in SHH-type medulloblastoma may reveal new therapeutic targets. Targeting SHH-type medulloblastoma: Medulloblastoma is a brain tumor that occurs mostly in children and has few therapeutic options. Attempts to block the Sonic Hedgehog (SHH) pathway that drives various subtypes of the tumor have been unsuccessful clinically. Dobson et al. found a mechanism by which SHH signaling may be increased in some patients. In a new mouse model, the authors found that increased expression of the transcriptional repressor REST in cells that give rise to the disease supports a more aggressive disease course by promoting epigenetic repression of the genes that encode PTCH1 and PTEN, thereby enhancing proliferative and migratory signaling by SHH and the kinase AKT. These findings reveal potential therapeutic targets for patients with high-REST, SHH-type medulloblastoma. In medulloblastomas (MBs), the expression and activity of RE1-silencing transcription factor (REST) is increased in tumors driven by the sonic hedgehog (SHH) pathway, specifically the SHH-α (children 3 to 16 years) and SHH-β (infants) subgroups. Neuronal maturation is greater in SHH-β than SHH-α tumors, but both correlate with poor overall patient survival. We studied the contribution of REST to MB using a transgenic mouse model (RESTTG) wherein conditional NeuroD2-controlled REST transgene expression in lineage-committed Ptch1+/− cerebellar granule neuron progenitors (CGNPs) accelerated tumorigenesis and increased penetrance and infiltrative disease. This model revealed a neuronal maturation context–specific antagonistic interplay between the transcriptional repressor REST and the activator GLI1 at Ptch1. Expression of Arrb1, which encodes β-arrestin1 (a GLI1 inhibitor), was substantially reduced in proliferating and, to a lesser extent, lineage-committed RESTTG cells compared with wild-type proliferating CGNPs. Lineage-committed RESTTG cells also had decreased GLI1 activity and increased histone H3K9 methylation at the Ptch1 locus, which correlated with premature silencing of Ptch1. These cells also had decreased expression of Pten, which encodes a negative regulator of the kinase AKT. Expression of PTCH1 and GLI1 were less, and ARRB1 was somewhat greater, in patient SHH-β than SHH-α MBs, whereas that of PTEN was similarly lower in both subtypes than in others. Inhibition of histone modifiers or AKT reduced proliferation and induced apoptosis, respectively, in cultured REST-high MB cells. Our findings linking REST to differentiation-specific chromatin remodeling, PTCH1 silencing, and AKT activation in MB tissues reveal potential subgroup-specific therapeutic targets for MB patients. [ABSTRACT FROM AUTHOR]

Glutathione S-transferase (GST) single nucleotide polymorphisms (SNPs) have been associated with a lower intellectual quotient (IQ) in medulloblastoma survivors. We investigated the association of GSTP1 polymorphisms with intellectual, neurocognitive skills (e.g., attention span, working memory, and processing speed), and adaptive outcomes for long-term pediatric medulloblastoma survivors. We hypothesized that genetic risk and sex-specific risk would contribute to significantly lower performances across all measures. Eighteen long-term pediatric medulloblastoma survivors completed the Wechsler Abbreviated Scale Intelligence, California Verbal Learning Test-II, Auditory Consonant Trigrams, and Oral Symbol Digit Modality Test. Informants were interviewed with the Scales of Independent Behavior-Revised (SIB-R). After controlling for the false discovery rate, females with a polymorphism performed significantly worse than females without a polymorphism on verbal IQ (p =.005) and SIB-R (p =.012). There was a significant interaction between sex and polymorphism status for verbal IQ (b = −1.8, SE = 0.827, CI: −3.58, −.036). The main effect of this interaction was significant for females (p =.004) and not for males (p =.557). We found large effect sizes between males with the polymorphism and females with the polymorphism across measures of attention span (g =.877), working memory (g = 1.12), and processing speed (g = 1.53). Female medulloblastoma survivors with a GSTP1 polymorphism may have increased vulnerability to deficits in core cognitive skills, IQ, and everyday functional outcomes. Sex-specific genetic risk contributes to the variability in long-term verbal intelligence for medulloblastoma survivors. [ABSTRACT FROM AUTHOR]

Y-box binding protein 1 (YBX1 or YB1) is a therapeutically relevant oncoprotein capable of RNA and DNA binding and mediating protein–protein interactions that drive proliferation, stemness, and resistance to platinum-based therapies. Given our previously published findings, the potential for YB1-driven cisplatin resistance in medulloblastoma (MB), and the limited studies exploring YB1-DNA repair protein interactions, we chose to investigate the role of YB1 in mediating radiation resistance in MB. MB, the most common pediatric malignant brain tumor, is treated with surgical resection, cranio-spinal radiation, and platinum-based chemotherapy, and could potentially benefit from YB1 inhibition. The role of YB1 in the response of MB to ionizing radiation (IR) has not yet been studied but remains relevant for determining potential anti-tumor synergy of YB1 inhibition with standard radiation therapy. We have previously shown that YB1 drives proliferation of cerebellar granular neural precursor cells (CGNPs) and murine Sonic Hedgehog (SHH) group MB cells. While others have demonstrated a link between YB1 and homologous recombination protein binding, functional and therapeutic implications remain unclear, particularly following IR-induced damage. Here we show that depleting YB1 in both SHH and Group 3 MB results not only in reduced proliferation but also synergizes with radiation due to differential response dynamics. YB1 silencing through shRNA followed by IR drives a predominantly NHEJ-dependent repair mechanism, leading to faster γH2AX resolution, premature cell cycle re-entry, checkpoint bypass, reduced proliferation, and increased senescence. These findings show that depleting YB1 in combination with radiation sensitizes SHH and Group 3 MB cells to radiation. [ABSTRACT FROM AUTHOR]

Detecting circulating tumor cells (CTCs) with high sensitivity and specificity is critical to management of metastatic cancers. Although immuno-magnetic technology for in vitro detection of CTCs has shown promising potential for clinical applications, the biofouling effect, i.e. , non-specific adhesion of biomolecules and non-cancerous cells in complex biological samples to the surface of a device/probe, can reduce the sensitivity and specificity of cell detection. Reported herein is the application of anti-biofouling polyethylene glycol- block -allyl glycidyl ether copolymer (PEG- b -AGE) coated iron oxide nanoparticles (IONPs) to improve the separation of targeted tumor cells from aqueous phase in an external magnetic field. PEG- b -AGE coated IONPs conjugated with transferrin (Tf) exhibited significant anti-biofouling properties against non-specific protein adsorption and off-target cell uptake, thus substantially enhancing the ability to target and separate transferrin receptor (TfR) over-expressed D556 medulloblastoma cells. Tf conjugated PEG- b -AGE coated IONPs exhibited a high capture rate of targeted tumor cells (D556 medulloblastoma cell) in cell media (58.7 ± 6.4%) when separating 100 targeted tumor cells from 1 × 10 5 non-targeted cells and 41 targeted tumor cells from 100 D556 medulloblastoma cells spiked into 1 mL blood. It is demonstrated that developed nanoparticle has higher efficiency in capturing targeted cells than widely used micron-sized particles ( i.e. , Dynabeads ® ). [ABSTRACT FROM AUTHOR]

Medulloblastoma (MB) is the most common pediatric brain malignancy and is divided into four molecularly distinct subgroups: WNT, Sonic Hedgehog (SHHp53mut and SHHp53wt), Group 3, and Group 4. Previous reports suggest that SHH MB features a unique tumor microenvironment compared with other MB groups. To better understand how SHH MB tumor cells interact with and potentially modify their microenvironment, we performed cytokine array analysis of culture media from freshly isolated MB patient tumor cells, spontaneous SHH MB mouse tumor cells and mouse and human MB cell lines. We found that the SHH MB cells produced elevated levels of IGFBP2 compared to non-SHH MBs. We confirmed these results using ELISA, western blotting, and immunofluorescence staining. IGFBP2 is a pleiotropic member of the IGFBP super-family with secreted and intracellular functions that can modulate tumor cell proliferation, metastasis, and drug resistance, but has been understudied in medulloblastoma. We found that IGFBP2 is required for SHH MB cell proliferation, colony formation, and cell migration, through promoting STAT3 activation and upregulation of epithelial to mesenchymal transition markers; indeed, ectopic STAT3 expression fully compensated for IGFBP2 knockdown in wound healing assays. Taken together, our findings reveal novel roles for IGFBP2 in SHH medulloblastoma growth and metastasis, which is associated with very poor prognosis, and they indicate an IGFBP2-STAT3 axis that could represent a novel therapeutic target in medulloblastoma. [ABSTRACT FROM AUTHOR]

( B E b ) shSCR and shYB1 non-treated and treated with 10 Gy were stained with LaminA/C and DAPI 48 h after 10 Gy irradiation. shSCR cells demonstrate more aberrations in nuclear morphology (UW228 and additional images Supp Fig. ( B C b ) -Gal stain of UW228 cells following radiation time course demonstrating increased senescence of YB1 depleted cells compared to irradiated control (5 Gy shSCR vs. 5 Gy shYB1 95% CI - 16.75-(- 5.09) I p i < 0.0001 two-way ANOVA, n = 3). ( B A3 b ) -Gal stain of ONS-76 cells following radiation time course demonstrating increased senescence of YB1 depleted cells compared to irradiated control (5 Gy shSCR vs. 5 Gy shYB1 95% CI - 22.64-(- 7.91) I p i < 0.0001 two-way ANOVA, n = 3). [Extracted from the article]

PURPOSE: Profiling of pediatric cancers through deep sequencing of large gene panels and whole exomes is rapidly being adopted in many clinical settings. However, the most impactful approach to genomic profiling of pediatric cancers remains to be defined. METHODS: We conducted a prospective precision medicine trial, using whole-exome sequencing of tumor and germline tissue and whole-transcriptome sequencing (RNA Seq) of tumor tissue to characterize the mutational landscape of 127 tumors from 126 unique patients across the spectrum of pediatric brain tumors, hematologic malignancies, and extracranial solid tumors. RESULTS: We identified somatic tumor alterations in 121/127 (95.3%) tumor samples and identified cancer predisposition syndromes on the basis of known pathogenic or likely pathogenic germline mutations in cancer predisposition genes in 9/126 patients (7.1%). Additionally, we developed a novel scoring system for measuring the impact of tumor and germline sequencing, encompassing therapeutically relevant genomic alterations, cancer-related germline findings, recommendations for treatment, and refinement of risk stratification or prognosis. At least one impactful finding from the genomic results was identified in 108/127 (85%) samples sequenced. A recommendation to consider a targeted agent was provided for 82/126 (65.1%) patients. Twenty patients ultimately received therapy with a molecularly targeted agent, representing 24% of those who received a targeted agent recommendation and 16% of the total cohort. CONCLUSION: Paired tumor/normal whole-exome sequencing and tumor RNA Seq of de novo or relapsed/refractory tumors was feasible and clinically impactful in high-risk pediatric cancer patients. [ABSTRACT FROM AUTHOR]

Background: Associations have been found between single nucleotide polymorphisms (SNPs) in the MTHFR gene and cognitive outcomes in cancer survivors. Prior research has demonstrated that the presence of MTHFR SNPs (rs1801131 and rs1801133) in survivors of acute lymphoblastic leukemia (ALL) corresponds to impairments in attention and executive functioning. The current study examines the associations between rs1801131 and/or rs1801133 SNPs and cognitive performance in long-term survivors of medulloblastoma. Procedure: Eighteen pediatric medulloblastoma survivors, on average 12.42 years post-diagnosis, completed the Digit Span Forward, Digit Span Backward, California Verbal Learning Test Trial 1, and Auditory Consonant Trigrams tests. MTHFR SNPs were detected using whole genome sequencing data and custom scripts within R software. Results: Survivors with a rs1801131 SNP performed significantly worse on Digit Span Backward than survivors without this SNP exhibiting a large effect (p = 0.049; d = 0.95). Survivors with a rs1801131 SNP performed worse on Digit Span Forward (d = 0.478) and the CVLT Trial 1 (d = 0.417) with medium effect sizes. In contrast to rs1801131, relationships were not identified between a rs1801133 SNP and these performance measures. Conclusions: Our findings demonstrate the potential links between MTHFR SNPs and cognitive outcomes following treatment in brain tumor survivors. The current findings establish a novel relationship between rs1801131 and working memory in medulloblastoma. Increases in homocysteine levels and oxidative damage from radiation may lead to adverse long-term outcomes. This establishes the need to look beyond leukemia and methotrexate treatment to consider the risk of MTHFR SNPs for medulloblastoma survivors. [ABSTRACT FROM AUTHOR]

BACKGROUND: Proton therapy may reduce cognitive deficits after radiotherapy among brain tumor survivors, although current data are limited to retrospective comparisons between historical cohorts. The authors compared intelligence quotient scores within a case‐matched cohort of children with medulloblastoma treated with proton radiation (PRT) or photon radiation (XRT) over the same time period. METHODS: Among 88 consecutive patients with standard‐risk medulloblastoma treated with PRT or XRT at 2 institutions from 2000 to 2009, 50 were matched 1:1 (25 with PRT and 25 with XRT) according to age, gender, date of diagnosis, histology, radiation boost, and craniospinal irradiation dose. One‐way analyses of variance were performed to compare the Full‐Scale Intelligence Quotient (FSIQ) and associated index scores between the 2 cohorts. RESULTS: Neurocognitive data were available for 37 survivors (17 with PRT and 20 with XRT) from the matched cohort. The mean age was 8.5 years (SD, 4.14 years). The median follow‐up was 5.3 years (range, 1.0‐11.4 years) and 4.6 years (range, 1.1‐11.2 years) for the PRT and XRT cohorts, respectively (P =.193). Patients treated with PRT had significantly higher mean FSIQ (99.6 vs 86.2; P =.021), verbal (105.2 vs 88.6; P =.010), and nonverbal scores (103.1 vs 88.9; P =.011) than the XRT‐treated cohort. Differences in processing speed (82.9 vs 77.2; P =.331) and working memory (97.0 vs 92.7; P =.388) were not statistically significant. CONCLUSIONS: Radiotherapy‐associated cognitive effects appear to be more attenuated after proton therapy. Comprehensive prospective studies are needed to appropriately evaluate the neurocognitive advantages of proton therapy. In this case‐matched, multi‐institutional analysis, children with standard‐risk medulloblastoma have been treated with surgery, chemotherapy, and either contemporary proton or photon radiation over the same time period. After a median follow‐up of 5 years between radiation and neurocognitive assessment, children treated with proton therapy have demonstrated significantly higher Full‐Scale Intelligence Quotient, verbal, and nonverbal scores. [ABSTRACT FROM AUTHOR]

Over the past decade, remarkable progress has been made towards elucidating the origin and genomic landscape of childhood high-grade brain tumours. It has become evident that paediatric high-grade gliomas differ from those in adults with respect to multiple defining aspects including: DNA copy number, gene expression profiles, tumour locations within the CNS and genetic alterations such as somatic histone mutations. Despite these advances, clinical trials for children with gliomas have historically been based on ineffective adult regimens that fail to take into consideration the fundamental biological differences between the two. Additionally, although our knowledge of the intrinsic cellular mechanisms driving tumour progression has considerably expanded, little is known about the dynamic tumour immune microenvironment in paediatric high-grade gliomas. In this review, we explore the genetic and epigenetic landscape of these gliomas and how this drives the creation of specific tumour subgroups with meaningful survival outcomes. Further, we provide a comprehensive analysis of the paediatric high-grade glioma tumour immune microenvironment and discuss emerging therapeutic efforts aimed at exploiting the immune functions of these tumours. [ABSTRACT FROM AUTHOR]

Objective: Children who suffer from brain insults (i.e., traumatic brain injury (TBI), chemotherapy and radiation treatment for brain tumors) are susceptible to late-emerging cognitive sequelae. Even with similar neurological risk variables, variability in long-term cognitive outcomes remains an area of investigation for researchers of acquired brain injury. Given the potential for genetic factors to influence response to chemoradiation, researchers have examined associations between germline, inherited, single nucleotide polymorphisms (SNPs), and neurocognitive outcomes for cancer survivors. Children who sustain an uncomplicated mild TBI generally recover without long-term neuropsychological consequences. However, TBI survivors have overlapping mechanism categories with cancer survivors through secondary injury variables that can be influenced by genomic variation (e.g., oxidative stress and neuroinflammation). Furthermore, the study of genomic vulnerability is limited in heterogenous groups of pediatric TBI survivors. This study aims to identify associations between genotype and long-term neurocognitive outcomes for acquired brain injury survivors by utilizing machine learning to uncover pathophysiological similarities and differences between groups. Participants and Methods: Fourteen brain tumor survivors, 139 traumatic brain injury survivors, and 63 healthy, age-matched controls completed the Letter N-back task to obtain performances on core neurocognitive skills (attention, working memory, and processing speed). Ten targeted genotypes were examined across five pathophysiological pathways (neurotransmission, oxidative stress, neuroinflammation, plasticity, growth and repair, and folate metabolism). Data were trained and tested utilizing three regression machine learning models. Mean estimated error and R2 were generated for each neurocognitive outcome. A feature importance score for models with positive variance was generated to determine how predictive a given SNP is for neurocognitive outcomes. Results: Genotype only accounted for a small amount of variance in cognitive outcomes when all clinical groups were combined. The mean absolute error for the best-fitting models from analyses where all groups were combined decreased when groups were examined separately; however, the differences in model R2 values were not significant. The relationship between brain tumor survivors and processing speed performance depended on genotype. Two SNPs had positive feature importance at the interaction level (rs58225473 and rs1801394). These SNPs are located on the CACNB2 and MTR genes and have functional consequences for neurotransmission and folate metabolism. Models of traumatic brain injury survivors did not explain positive variance and could not be examined for feature importance. Additionally, even when removing the only mechanism of action that should not be relevant for TBI survivors (folate metabolism polymorphisms), the TBI models still did not explain positive variance. Conclusions: Findings of the importance of two key SNPs on MTR and CACNB2 genes align with recent systematic reviews, which found associations between these polymorphisms and neuropsychological outcomes in more than one group or cohort of pediatric cancer survivors. Models for TBI survivors were limited by the heterogeneity of the group and ceiling effects on performance. An understanding of genetic vulnerabilities influenced by treatment and injury-related factors in acquired brain injury will inform our understanding of the developing and recovering childhood brain. The current study is an initial contribution to this goal and highlights the utility of machine learning methodology for future studies that examine the influence of genetic heterogeneity in pediatric acquired brain injury. [ABSTRACT FROM AUTHOR]

Medulloblastoma (MB), the most common malignant pediatric brain tumor, has high propensity to metastasize. Currently, the standard treatment for MB patients includes radiation therapy administered to the entire brain and spine for the purpose of treating or preventing against metastasis. Due to this aggressive treatment, the majority of long-term survivors will be left with permanent and debilitating neurocognitive impairment, for the 30–40% patients that fail to respond to treatment, all will relapse with terminal metastatic disease. An understanding of the underlying biology that drives MB metastasis is lacking, and is critically needed in order to develop targeted therapeutics for its prevention. To examine the metastatic biology of sonic hedgehog (SHH) MB, the human MB subgroup with the worst clinical outcome in children, we first generated a robust SmoA1-Math-GFP mouse model that reliably reproduces human SHH MB whereby metastases can be visualized under fluorescence microscopy. Lipidome alterations associated with metastasis were then investigated by applying ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) under positive ionization mode to primary tumor samples collected from mice without (n = 18) and with (n = 7) metastasis. Thirty-four discriminant lipids associated with SHH MB metastasis were successfully annotated, including ceramides (Cers), sphingomyelins (SMs), triacylglycerols (TGs), diacylglycerols (DGs), phosphatidylcholines (PCs), and phosphatidic acids (PAs). This study provides deeper insights into dysregulations of lipid metabolism associated with SHH MB metastatic progression, and thus serves as a guide toward novel targeted therapies. [ABSTRACT FROM AUTHOR]

Response criteria for paediatric high-grade glioma vary historically and across different cooperative groups. The Response Assessment in Neuro-Oncology working group developed response criteria for adult high-grade glioma, but these were not created to meet the unique challenges in children with the disease. The Response Assessment in Pediatric Neuro-Oncology (RAPNO) working group, consisting of an international panel of paediatric and adult neuro-oncologists, clinicians, radiologists, radiation oncologists, and neurosurgeons, was established to address issues and unique challenges in assessing response in children with CNS tumours. We established a subcommittee to develop response assessment criteria for paediatric high-grade glioma. Current practice and literature were reviewed to identify major challenges in assessing the response of paediatric high-grade gliomas to various treatments. For areas in which scientific investigation was scarce, consensus was reached through an iterative process. RAPNO response assessment recommendations include the use of MRI of the brain and the spine, assessment of clinical status, and the use of corticosteroids or antiangiogenics. Imaging standards for brain and spine are defined. Compared with the recommendations for the management of adult high-grade glioma, for paediatrics there is inclusion of diffusion-weighted imaging and a higher reliance on T2-weighted fluid-attenuated inversion recovery. Consensus recommendations and response definitions have been established and, similar to other RAPNO recommendations, prospective validation in clinical trials is warranted. [ABSTRACT FROM AUTHOR]

Introduction: Diffuse leptomeningeal glioneuronal tumors (DLGT) have been recognized in the most recent WHO classification as a distinct entity. Objective: We describe seven pediatric cases of DLGT and the responses to therapy and outcome. Methods: We conducted a retrospective review of charts from 1985 to 2013. Results: DBS is an effective therapeutic modality for intractable TLE, particularly in patients with lateralized EEG A total of seven patients were identified. Median age at diagnosis was 3 years. Three months was the median time from symptom development to diagnosis. Common MRI findings included diffuse leptomeningeal thickening, nodularity, or coating of the subarachnoid or ependymal surfaces. The leptomeningeal lesions often appear cystic and contrast enhancement was variable. Six patients had leptomeningeal involvement of the brain and spine. All patients had a negative CSF cytology. Biopsies demonstrated thickened meninges infiltrated by a monotonous population of oligodendrocyte-like cells. Immunohistochemistry revealed variable features of neuronal and/or glial differentiation. All samples were negative for BRAF V600E mutation by immunohistochemistry. Therapy included one patient treated with craniospinal irradiation followed by vincristine, etoposide, cyclophosphamide, and cisplatin with stable disease for 164 months. Six patients received carboplatin and vincristine with a median duration of response of 20+ months (15-122+). Three patients received temozolomide upfront and progressed at 3, 4, and 27 months. No patients demonstrated complete or partial responses to any chemotherapy regimens. Progression-free survival ranged from 3 to 164+ months; 4/7 patients remained free of progression. All patients are alive. Conclusions: DLGT are rare tumors that lack imaging responses; however, there was clinical/ symptom improvement in 100% of the patients. A better understanding of the tumor biology is necessary to improve the diagnosis and treatment of this rare disease. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to compare long-term disease control and overall survival between children treated with proton and photon radiation therapy (RT) for standard-risk medulloblastoma.Methods and Materials: This multi-institution cohort study includes 88 children treated with chemotherapy and proton (n=45) or photon (n=43) RT between 2000 and 2009. Overall survival (OS), recurrence-free survival (RFS), and patterns of failure were compared between the 2 cohorts.Results: Median (range) age was 6 years old at diagnosis (3-21 years) for proton patients versus 8 years (3-19 years) for photon patients (P=.011). Cohorts were similar with respect to sex, histology, extent of surgical resection, craniospinal irradiation (CSI) RT dose, total RT dose, whether the RT boost was delivered to the posterior fossa (PF) or tumor bed (TB), time from surgery to RT start, or total duration of RT. RT consisted of a median (range) CSI dose of 23.4 Gy (18-27 Gy) and a boost of 30.6 Gy (27-37.8 Gy). Median follow-up time is 6.2 years (95% confidence interval [CI]: 5.1-6.6 years) for proton patients versus 7.0 years (95% CI: 5.8-8.9 years) for photon patients. There was no significant difference in RFS or OS between patients treated with proton versus photon RT; 6-year RFS was 78.8% versus 76.5% (P=.948) and 6-year OS was 82.0% versus 87.6%, respectively (P=.285). On multivariate analysis, there was a trend for longer RFS with females (P=.058) and higher CSI dose (P=.096) and for longer OS with females (P=.093). Patterns of failure were similar between the 2 cohorts (P=.908).Conclusions: Disease control with proton and photon radiation therapy appears equivalent for standard risk medulloblastoma. [ABSTRACT FROM AUTHOR]

Medulloblastoma comprises four distinct molecular variants with distinct genetics, transcriptomes, and outcomes. Subgroup affiliation has been previously shown to remain stable at the time of recurrence, which likely reflects their distinct cells of origin. However, a therapeutically relevant question that remains unanswered is subgroup stability in the metastatic compartment. We assembled a cohort of 12-paired primary-metastatic tumors collected in the MAGIC consortium, and established their molecular subgroup affiliation by performing integrative gene expression and DNA methylation analysis. Frozen tissues were collected and profiled using Affymetrix gene expression arrays and Illumina methylation arrays. Class prediction and hierarchical clustering were performed using existing published datasets. Our molecular analysis, using consensus integrative genomic data, establishes the unequivocal maintenance of molecular subgroup affiliation in metastatic medulloblastoma. We further validated these findings by interrogating a non-overlapping cohort of 19 pairs of primary-metastatic tumors from the Burdenko Neurosurgical Institute using an orthogonal technique of immunohistochemical staining. This investigation represents the largest reported primary-metastatic paired cohort profiled to date and provides a unique opportunity to evaluate subgroup-specific molecular aberrations within the metastatic compartment. Our findings further support the hypothesis that medulloblastoma subgroups arise from distinct cells of origin, which are carried forward from ontogeny to oncology. [ABSTRACT FROM AUTHOR]

Medulloblastoma (MB) expresses Src kinase, while aurora kinase A overexpression correlates with poor survival. We thus investigated novel combination treatment with dasatinib and AT9283, inhibitors of Src and aurora kinase, respectively, on MB growth in vitro and in vivo . Treatment with each drug significantly reduced cell viability and combined treatment markedly potentiated this response. AT9283 induced p53 expression, autophagy, and G2/M cell-cycle arrest, while combined treatment induced S phase arrest. Dasatinib treatment caused tumor regression in vivo . Activated Src was detected in 44% MB analyzed. We conclude that further evaluation of this combination therapy for MB is highly warranted. [ABSTRACT FROM AUTHOR]

Diffuse intrinsic pontine glioma (DIPG) is a highly morbid form of pediatric brainstem glioma. Here, we present the first comprehensive protein, mRNA, and methylation profiles of fresh-frozen DIPG specimens ( n = 14), normal brain tissue ( n = 10), and other pediatric brain tumors ( n = 17). Protein profiling identified 2,305 unique proteins indicating distinct DIPG protein expression patterns compared to other pediatric brain tumors. Western blot and immunohistochemistry validated upregulation of Clusterin (CLU), Elongation Factor 2 (EF2), and Talin-1 (TLN1) in DIPGs studied. Comparisons to mRNA expression profiles generated from tumor and adjacent normal brain tissue indicated two DIPG subgroups, characterized by upregulation of Myc (N-Myc) or Hedgehog (Hh) signaling. We validated upregulation of PTCH, a membrane receptor in the Hh signaling pathway, in a subgroup of DIPG specimens. DNA methylation analysis indicated global hypomethylation of DIPG compared to adjacent normal tissue specimens, with differential methylation of 24 genes involved in Hh and Myc pathways, correlating with protein and mRNA expression patterns. Sequencing analysis showed c.83A>T mutations in the H3F3A or HIST1H3B gene in 77 % of our DIPG cohort. Supervised analysis revealed a unique methylation pattern in mutated specimens compared to the wild-type DIPG samples. This study presents the first comprehensive multidimensional protein, mRNA, and methylation profiling of pediatric brain tumor specimens, detecting the presence of two subgroups within our DIPG cohort. This multidimensional analysis of DIPG provides increased analytical power to more fully explore molecular signatures of DIPGs, with implications for evaluating potential molecular subtypes and biomarker discovery for assessing response to therapy. [ABSTRACT FROM AUTHOR]

Purpose: Chemotherapy for relapsed medulloblastoma has been inadequate, and most patients succumb to disease. Methods: We retrospectively reviewed nine cases of relapsed medulloblastoma treated with bevacizumab, irinotecan, ± temozolomide. Patients received one to three prior therapeutic regimens. Five patients received 10 mg/kg bevacizumab and 125-150 mg/m irinotecan IV every 2 weeks, with temozolomide, starting at a median dose of 150 mg/m orally for 5 days monthly. Two patients received bevacizumab and irinotecan, but not temozolomide, due to provider preference. Two of nine patients received 15 mg/kg bevacizumab IV, 90 mg/m irinotecan orally for five consecutive days, 100 mg/m/day temozolomide IV for 5 days, and 1.5 mg/m vincristine IV, each administered every 21 days. Results: Median time to progression was 11 months. Median overall survival was 13 months. Objective tumor response at 3 months was 67 %, including six patients with partial response (PR) and three patients with stable disease (SD). At 6 months, objective response was 55 %, with two patients with PR and three with complete response. Additionally, one patient had SD and three had PD. Two patients remain alive and progression free at 15 and 55 months; another is alive with disease at 20 months. Toxicities included two patients with grade III neutropenia, two with grade III thrombocytopenia, one with grade III elevation of liver function tests, and one patient with grade III diarrhea. Conclusions: The combination of bevacizumab and irinotecan, with or without temozolomide, produces objective responses with minimal toxicity in children with recurrent medulloblastoma. Prospective clinical trials are needed to evaluate the efficacy of this strategy. [ABSTRACT FROM AUTHOR]