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5.  BCAT1 promotes cell proliferation through amino acid catabolism in gliomas carrying wild-type IDH1 
Nature medicine  2013;19(7):901-908.
Here we show that glioblastoma express high levels of branched-chain amino acid transaminase 1 (BCAT1), the enzyme that initiates the catabolism of branched-chain amino acids (BCAAs). Expression of BCAT1 was exclusive to tumors carrying wild-type isocitrate dehydrogenase 1 (IDH1) and IDH2 genes and was highly correlated with methylation patterns in the BCAT1 promoter region. BCAT1 expression was dependent on the concentration of α-ketoglutarate substrate in glioma cell lines and could be suppressed by ectopic overexpression of mutant IDH1 in immortalized human astrocytes, providing a link between IDH1 function and BCAT1 expression. Suppression of BCAT1 in glioma cell lines blocked the excretion of glutamate and led to reduced proliferation and invasiveness in vitro, as well as significant decreases in tumor growth in a glioblastoma xenograft model. These findings suggest a central role for BCAT1 in glioma pathogenesis, making BCAT1 and BCAA metabolism attractive targets for the development of targeted therapeutic approaches to treat patients with glioblastoma.
doi:10.1038/nm.3217
PMCID: PMC4916649  PMID: 23793099
12.  IDH mutant diffuse and anaplastic astrocytomas have similar age at presentation and little difference in survival: a grading problem for WHO 
Acta neuropathologica  2015;129(6):867-873.
The WHO 2007 classification of tumors of the CNS distinguishes between diffuse astrocytoma WHO grade II (A IIWHO2007) and anaplastic astrocytoma WHO grade III (AA III WHO2007). Patients with A II WHO2007 are significantly younger and survive significantly longer than those with AA III WHO2007. So far, classification and grading relies on morphological grounds only and does not yet take into account IDH status, a molecular marker of prognostic relevance. We here demonstrate that WHO 2007 grading performs poorly in predicting prognosis when applied to astrocytoma carrying IDH mutations. Three independent series including a total of 1360 adult diffuse astrocytic gliomas with IDH mutation containing 683 A II IDHmut, 562 AA III IDHmut and 115 GBM IDHmut have been examined for age distribution and survival. In all three series patients with A II IDHmut and AA III IDHmut were of identical age at presentation of disease (36–37 years) and the difference in survival between grades was much less (10.9 years for A II IDHmut, 9.3 years for AA III IDHmut) than that reported for A II WHO2007 versus AA III WHO2007. Our analyses imply that the differences in age and survival between A II WHO2007 and AA III WHO2007 predominantly depend on the fraction of IDH-non-mutant astrocytomas in the cohort. This data poses a substantial challenge for the current practice of astrocytoma grading and risk stratification and is likely to have far-reaching consequences on the management of patients with IDH-mutant astrocytoma.
doi:10.1007/s00401-015-1438-8
PMCID: PMC4500039  PMID: 25962792
13.  Medulloblastoma-associated DDX3 variant selectively alters the translational response to stress 
Oncotarget  2016;7(19):28169-28182.
DDX3X encodes a DEAD-box family RNA helicase (DDX3) commonly mutated in medulloblastoma, a highly aggressive cerebellar tumor affecting both children and adults. Despite being implicated in several facets of RNA metabolism, the nature and scope of DDX3′s interactions with RNA remain unclear. Here, we show DDX3 collaborates extensively with the translation initiation machinery through direct binding to 5′UTRs of nearly all coding RNAs, specific sites on the 18S rRNA, and multiple components of the translation initiation complex. Impairment of translation initiation is also evident in primary medulloblastomas harboring mutations in DDX3X, further highlighting DDX3′s role in this process. Arsenite-induced stress shifts DDX3 binding from the 5′UTR into the coding region of mRNAs concomitant with a general reduction of translation, and both the shift of DDX3 on mRNA and decreased translation are blunted by expression of a catalytically-impaired, medulloblastoma-associated DDX3R534H variant. Furthermore, despite the global repression of translation induced by arsenite, translation is preserved on select genes involved in chromatin organization in DDX3R534H-expressing cells. Thus, DDX3 interacts extensively with RNA and ribosomal machinery to help remodel the translation landscape in response to stress, while cancer-related DDX3 variants adapt this response to selectively preserve translation.
doi:10.18632/oncotarget.8612
PMCID: PMC5053718  PMID: 27058758
medulloblastoma; DDX3X; DDX3; RNA helicase; CLIP-seq
14.  Molecular Classification of Ependymal Tumors across All CNS Compartments, Histopathological Grades, and Age Groups 
Cancer cell  2015;27(5):728-743.
Ependymal tumors across age groups are currently classified and graded solely by histopathology. It is, however, commonly accepted that this classification scheme has limited clinical utility based on its lack of reproducibility in predicting patients’ outcome. We aimed at establishing a uniform molecular classification using DNA methylation profiling. Nine molecular subgroups were identified in a large cohort of 500 tumors, 3 in each anatomical compartment of the CNS, spine, posterior fossa, supratentorial. Two supratentorial subgroups are characterized by prototypic fusion genes involving RELA and YAP1, respectively. Regarding clinical associations, the molecular classification proposed herein outperforms the current histopathological classification and thus might serve as a basis for the next World Health Organization classification of CNS tumors.
Graphical Abstract
doi:10.1016/j.ccell.2015.04.002
PMCID: PMC4712639  PMID: 25965575
15.  Assessing CpG island methylator phenotype, 1p/19q codeletion, and MGMT promoter methylation from epigenome-wide data in the biomarker cohort of the NOA-04 trial 
Neuro-Oncology  2014;16(12):1630-1638.
Background
Molecular biomarkers including isocitrate dehydrogenase 1 or 2 (IDH1/2) mutation, 1p/19q codeletion, and O6-methylguanine-DNA-methyltransferase (MGMT) promoter methylation may improve prognostication and guide treatment decisions for patients with World Health Organization (WHO) anaplastic gliomas. At present, each marker is individually tested by distinct assays. Illumina Infinium HumanMethylation450 BeadChip arrays (HM450) enable the determination of large-scale methylation profiles and genome-wide DNA copy number changes. Algorithms have been developed to detect the glioma CpG island methylator phenotype (G-CIMP) associated with IDH1/2 mutation, 1p/19q codeletion, and MGMT promoter methylation using a single assay.
Methods
Here, we retrospectively investigated the diagnostic and prognostic performance of these algorithms in comparison to individual marker testing and patient outcome in the biomarker cohort (n = 115 patients) of the NOA-04 trial.
Results
Concordance for IDH and 1p/19q status was very high: In 92% of samples, the HM450 and reference data agreed. In discordant samples, survival analysis by Kaplan-Meier and Cox regression analyses suggested a more accurate assessment of biological phenotype by the HM450 analysis. The HM450-derived MGMT-STP27 model to calculate MGMT promoter methylation probability revealed this aberration in a significantly higher fraction of samples than conventional methylation-specific PCR, with 87 of 91 G-CIMP tumors predicted as MGMT promoter-methylated. Pyrosequencing of discordant samples confirmed the HM450 assessment in 14 of 17 cases.
Conclusions
G-CIMP and 1p/19q codeletion are reliably detectable by HM450 analysis and are associated with prognosis in the NOA-04 trial. For MGMT, HM450 suggests promoter methylation in the vast majority of G-CIMP tumors, which is supported by pyrosequencing.
doi:10.1093/neuonc/nou138
PMCID: PMC4232086  PMID: 25028501
450k; 1p/19q; anaplastic glioma; G-CIMP; MGMT
16.  Enhancer hijacking activates GFI1 family oncogenes in medulloblastoma 
Northcott, Paul A | Lee, Catherine | Zichner, Thomas | Stütz, Adrian M | Erkek, Serap | Kawauchi, Daisuke | Shih, David JH | Hovestadt, Volker | Zapatka, Marc | Sturm, Dominik | Jones, David TW | Kool, Marcel | Remke, Marc | Cavalli, Florence | Zuyderduyn, Scott | Bader, Gary | VandenBerg, Scott | Esparza, Lourdes Adriana | Ryzhova, Marina | Wang, Wei | Wittmann, Andrea | Stark, Sebastian | Sieber, Laura | Seker-Cin, Huriye | Linke, Linda | Kratochwil, Fabian | Jäger, Natalie | Buchhalter, Ivo | Imbusch, Charles D | Zipprich, Gideon | Raeder, Benjamin | Schmidt, Sabine | Diessl, Nicolle | Wolf, Stephan | Wiemann, Stefan | Brors, Benedikt | Lawerenz, Chris | Eils, Jürgen | Warnatz, Hans-Jörg | Risch, Thomas | Yaspo, Marie-Laure | Weber, Ursula D | Bartholomae, Cynthia C | von Kalle, Christof | Turányi, Eszter | Hauser, Peter | Sanden, Emma | Darabi, Anna | Siesjö, Peter | Sterba, Jaroslav | Zitterbart, Karel | Sumerauer, David | van Sluis, Peter | Versteeg, Rogier | Volckmann, Richard | Koster, Jan | Schuhmann, Martin U | Ebinger, Martin | Grimes, H. Leighton | Robinson, Giles W | Gajjar, Amar | Mynarek, Martin | von Hoff, Katja | Rutkowski, Stefan | Pietsch, Torsten | Scheurlen, Wolfram | Felsberg, Jörg | Reifenberger, Guido | Kulozik, Andreas E | von Deimlmg, Andreas | Witt, Olaf | Eils, Roland | Gilbertson, Richard J | Korshunov, Andrey | Taylor, Michael D | Lichter, Peter | Korbel, Jan O | Wechsler-Reya, Robert J | Pfister, Stefan M
Nature  2014;511(7510):428-434.
Summary Paragraph
Medulloblastoma is a highly malignant paediatric brain tumour currently treated with a combination of surgery, radiation, and chemotherapy, posing a considerable burden of toxicity to the developing child. Genomics has illuminated the extensive intertumoural heterogeneity of medulloblastoma, identifying four distinct molecular subgroups. Group 3 and Group 4 subgroup medulloblastomas account for the majority of paediatric cases; yet, oncogenic drivers for these subtypes remain largely unidentified. Here we describe a series of prevalent, highly disparate genomic structural variants, restricted to Groups 3 and 4, resulting in specific and mutually exclusive activation of the growth factor independent 1 family protooncogenes, GFI1 and GFI1B. Somatic structural variants juxtapose GFI1/GFI1B coding sequences proximal to active enhancer elements, including super-enhancers, instigating oncogenic activity. Our results, supported by evidence from mouse models, identify GFI1 and GFI1B as prominent medulloblastoma oncogenes and implicate ‘enhancer hijacking’ as an efficient mechanism driving oncogene activation in a childhood cancer.
doi:10.1038/nature13379
PMCID: PMC4201514  PMID: 25043047
17.  Somatic CRISPR/Cas9-mediated tumor suppressor disruption enables versatile brain tumor modeling 
Nature communications  2015;6:7391.
In vivo functional investigation of oncogenes using somatic gene transfer has been successfully exploited to validate their role in tumorigenesis. For tumor suppressor genes this has proven more challenging due to technical aspects. In order to provide a flexible and effective method for investigating somatic loss-of-function alterations and their influence on tumorigenesis, we have established CRISPR/Cas9-mediated somatic gene disruption, allowing for in vivo targeting of TSGs. Here we demonstrate the utility of this approach by deleting single (Ptch1) or multiple genes (Trp53, Pten, Nf1) in the mouse brain resulting in the development of medulloblastoma and glioblastoma, respectively. Using whole genome sequencing (WGS) we characterized the medulloblastoma-driving Ptch1 deletions in detail and show that no off-targets were detected in these tumors. This method provides a fast and convenient system for validating the emerging wealth of novel candidate tumor suppressor genes and the generation of faithful animal models of human cancer.
doi:10.1038/ncomms8391
PMCID: PMC4467376  PMID: 26067104
18.  Genome Sequencing of SHH Medulloblastoma Predicts Genotype-Related Response to Smoothened Inhibition 
Kool, Marcel | Jones, David T.W. | Jäger, Natalie | Northcott, Paul A. | Pugh, Trevor J. | Hovestadt, Volker | Piro, Rosario M. | Esparza, L. Adriana | Markant, Shirley L. | Remke, Marc | Milde, Till | Bourdeaut, Franck | Ryzhova, Marina | Sturm, Dominik | Pfaff, Elke | Stark, Sebastian | Hutter, Sonja | Şeker-Cin, Huriye | Johann, Pascal | Bender, Sebastian | Schmidt, Christin | Rausch, Tobias | Shih, David | Reimand, Jüri | Sieber, Laura | Wittmann, Andrea | Linke, Linda | Witt, Hendrik | Weber, Ursula D. | Zapatka, Marc | König, Rainer | Beroukhim, Rameen | Bergthold, Guillaume | van Sluis, Peter | Volckmann, Richard | Koster, Jan | Versteeg, Rogier | Schmidt, Sabine | Wolf, Stephan | Lawerenz, Chris | Bartholomae, Cynthia C. | von Kalle, Christof | Unterberg, Andreas | Herold-Mende, Christel | Hofer, Silvia | Kulozik, Andreas E. | von Deimling, Andreas | Scheurlen, Wolfram | Felsberg, Jörg | Reifenberger, Guido | Hasselblatt, Martin | Crawford, John R. | Grant, Gerald A. | Jabado, Nada | Perry, Arie | Cowdrey, Cynthia | Croul, Sydney | Zadeh, Gelareh | Korbel, Jan O. | Doz, Francois | Delattre, Olivier | Bader, Gary D. | McCabe, Martin G. | Collins, V. Peter | Kieran, Mark W. | Cho, Yoon-Jae | Pomeroy, Scott L. | Witt, Olaf | Brors, Benedikt | Taylor, Michael D. | Schüller, Ulrich | Korshunov, Andrey | Eils, Roland | Wechsler-Reya, Robert J. | Lichter, Peter | Pfister, Stefan M.
Cancer cell  2014;25(3):393-405.
Summary
Smoothened (SMO) inhibitors recently entered clinical trials for sonic-hedgehog-driven medulloblastoma (SHH-MB). Clinical response is highly variable. To understand the mechanism(s) of primary resistance and identify pathways cooperating with aberrant SHH signaling, we sequenced and profiled a large cohort of SHH-MBs (n = 133). SHH pathway mutations involved PTCH1 (across all age groups), SUFU (infants, including germline), and SMO (adults). Children >3 years old harbored an excess of downstream MYCN and GLI2 amplifications and frequent TP53 mutations, often in the germline, all of which were rare in infants and adults. Functional assays in different SHH-MB xenograft models demonstrated that SHH-MBs harboring a PTCH1 mutation were responsive to SMO inhibition, whereas tumors harboring an SUFU mutation or MYCN amplification were primarily resistant.
doi:10.1016/j.ccr.2014.02.004
PMCID: PMC4493053  PMID: 24651015
19.  Somatic CRISPR/Cas9-mediated tumour suppressor disruption enables versatile brain tumour modelling 
Nature Communications  2015;6:7391.
In vivo functional investigation of oncogenes using somatic gene transfer has been successfully exploited to validate their role in tumorigenesis. For tumour suppressor genes this has proven more challenging due to technical aspects. To provide a flexible and effective method for investigating somatic loss-of-function alterations and their influence on tumorigenesis, we have established CRISPR/Cas9-mediated somatic gene disruption, allowing for in vivo targeting of TSGs. Here we demonstrate the utility of this approach by deleting single (Ptch1) or multiple genes (Trp53, Pten, Nf1) in the mouse brain, resulting in the development of medulloblastoma and glioblastoma, respectively. Using whole-genome sequencing (WGS) we characterized the medulloblastoma-driving Ptch1 deletions in detail and show that no off-targets were detected in these tumours. This method provides a fast and convenient system for validating the emerging wealth of novel candidate tumour suppressor genes and the generation of faithful animal models of human cancer.
Gene transfer is a powerful technique to investigate the mechanistic basis of tumorigenesis. Here Zuckermann et al. adapt CRISPR/Cas9 genome editing to target potential oncogenes somatically in vivo, establishing a fast and convenient system for validating novel genetic candidates.
doi:10.1038/ncomms8391
PMCID: PMC4467376  PMID: 26067104
20.  NEXT-GENERATION NEUROPATHOLOGY - IMPROVING DIAGNOSTIC ACCURACY FOR BRAIN TUMORS USING DNA METHYLATION ARRAY-BASED MOLECULAR PROFILING 
Neuro-Oncology  2014;16(Suppl 3):iii4.
BACKGROUND: The current World Health Organisation (WHO) classification of central nervous system tumors comprises over 100 entities. Most of these are defined by purely histological criteria, with varying and sometimes overlapping spectra. Histological diagnosis is often challenging, however, especially in cases with limited or non-representative biopsy material. Thus, molecular technologies that can complement standard pathology testing have the potential to greatly enhance diagnostic precision and improve clinical decision-making. DNA methylation profiling, acting as a 'fingerprint' of cellular origin and molecular alterations, is one such promising technology. METHODS: We have assembled a reference dataset of more than 2,000 methylation profiles using the Illumina HumanMethylation450 (450k) array, currently representing over 50 brain tumor entities or subgroups. The array platform is suitable for both frozen and paraffin-embedded material, with minimal DNA input required. Each new diagnostic case receives an entity prediction with an associated probability score as a confidence measure. Genome-wide copy number profiles (e.g. for scoring 1p/19q loss or gene amplifications) and target gene methylation data (e.g. MGMT) generated from the array provide important additional information. RESULTS: In addition to the reference cohort, more than 500 diagnostic samples from Heidelberg University Hospital and external institutions have been processed. Approximately 5-10% of cases displayed a discrepancy between histological and molecular diagnoses. Careful re-examination of these often resulted in refinement of the original diagnosis, and improved patient care.Furthermore, samples collected for the reference cohort have led to significant improvements in our understanding of the biology of several tumor types, including the identification of further subgroups for several entities and associations with recurrent copy number changes and/or mutations. CONCLUSIONS: Our understanding of the molecular alterations underlying brain tumors has grown enormously in recent years, and it is crucial that this is translated into the clinic promptly. DNA methylation profiling is one tool with the potential to become an important part of the diagnostic armoury of neuropathologists. This relatively inexpensive and robust method is well suited to complement standard histopathologic techniques and improve diagnostic accuracy, thereby optimising patient management. We are currently expanding our pipeline to include additional diagnostic centres, allowing for further refinement and validation as well as broader international access. SECONDARY CATEGORY: Tumor Biology.
doi:10.1093/neuonc/nou206.13
PMCID: PMC4144477
21.  PROGNOSTIC AND PREDICTIVE BIOMARKER-BASED SUBGROUPS IN THE NOA-04 TRIAL 
Neuro-Oncology  2014;16(Suppl 3):iii4.
BACKGROUND: The WHO classification, based on morphological criteria, may be increasingly supplemented with defined molecular aberrations. These might help to resolve the discrepancy between classification and clinical outcome. Molecular biomarkers, including isocitrate dehydrogenase 1 or 2 (IDH1/2) mutation, 1p/19q codeletion, mutations and (consequently) loss of expression of alpha-thalassemia/mental retardation syndrome X-linked (ATRX) and O6-methylguanine-DNA-methyltransferase (MGMT) promoter methylation, improve prognostication and may even guide treatment decisions in patients with anaplastic gliomas. Illumina Infinium HumanMethylation450 BeadChip arrays (HM450) allow the determination of large-scale methylation profiles and genome-wide DNA copy number changes, enabling molecular subgrouping of tumors. In addition, algorithms have been developed to detect the glioma CpG island methylator phenotype (G-CIMP) associated with IDH1/2 mutation, 1p/19q codeletion and MGMT promoter methylation using this assay. METHODS: In the biomarker cohort of the NOA-04 trial, the diagnostic and prognostic performance of these molecular markers using single tests, HM450 data and HM450-based algorithms has been investigated to propose biological subgroups, which reflect outcomes and potentially influence treatment decisions. RESULTS: Loss of ATRX expression was detected in 45% of anaplastic astrocytomas (AA), 27% of anaplastic oligoastrocytomas (AOA) and 10% of anaplastic oligodendrogliomas (AO). It was mostly restricted to IDH mutant tumors and almost mutually exclusive with 1p/19q co-deletion. In tumors with IDH1 mutation, MGMT promoter methylation was associated with prolonged progression-free survival (PFS) with chemotherapy or radiotherapy (RT), and thus prognostic. In tumors without IDH1 mutation, MGMT promoter methylation was associated with increased PFS in patients treated with chemotherapy, too, but not in those who received RT alone as the first-line treatment, and is thus chemotherapy-predictive. Comparisons of single assays and HM450-based algorithms revealed a high concordance for IDH and 1p/19q status. The HM450-derived MGMT-STP27 model to calculate MGMT promoter methylation probability revealed this aberration in a significantly higher fraction of cases as conventional methylation-specific PCR, with 87/91 G-CIMP-positive tumors predicted as MGMT promoter-methylated. CONCLUSIONS: ATRX loss is a hallmark and favorable prognosticator of astrocytic tumors allowing a better definition of the clinically and morphologically mixed group of AOA. MGMT promoter methylation is a predictive biomarker for benefit from alkylating agent chemotherapy in patients with IDH1-wildtype, but not IDH1-mutant malignant gliomas of WHO grades III/IV. Combined IDH1/ MGMT assessment may help to individualize clinical decision making in neurooncology. G-CIMP and 1p/19q codeletion are reliably detectable by HM450 analysis and associated with prognosis in the NOA-04 trial. HM450 arrays allowed clustering of anaplastic gliomas into relevant subgroups. SECONDARY CATEGORY: Tumor Biology.
doi:10.1093/neuonc/nou206.14
PMCID: PMC4144478
22.  PROGNOSTIC SIGNIFICANCE OF CLINICAL, HISTOPATHOLOGICAL, AND MOLECULAR CHARACTERISTICS OF MEDULLOBLASTOMAS IN THE PROSPECTIVE HIT2000 MULTICENTER CLINICAL TRIAL COHORT 
Neuro-Oncology  2014;16(Suppl 3):iii24-iii25.
BACKGROUND: This study aimed to prospectively evaluate clinical, histopathological and molecular variables for outcome prediction in medulloblastoma patients. METHODS: Patients from the HIT2000 cooperative clinical trial were prospectively enrolled based on the availability of sufficient tumor material and complete clinical information. This revealed a cohort of 184 patients (median age 7.6 years), which was randomly split at a 2:1 ratio into a training (n = 127), and a validation (n = 57) dataset. All samples were subjected to thorough histopathological investigation, CTNNB1 mutation analysis, quantitative PCR, MLPA and FISH analyses for cytogenetic variables, and methylome analysis. RESULTS: By univariable analysis, clinical factors (M-stage), histopathological variables (large cell component, endothelial proliferation, synaptophysin pattern), and molecular features (chromosome 6q status, MYC amplification, TOP2A copy-number, subgrouping) were found to be prognostic. Molecular consensus subgrouping (WNT, SHH, Group 3, Group 4) was validated as an independent feature to stratify patients into different risk groups. When comparing methods for the identification of WNT-driven medulloblastoma, this study identified CTNNB1 sequencing and methylation profiling to most reliably identify these patients. After removing patients with particularly favorable (CTNNB1 mutation, extensive nodularity) or unfavorable (MYC amplification) markers, a risk score for the remaining “intermediate molecular risk” population dependent on age, M-stage, pattern of synaptophysin expression, and MYCN copy-number status was identified and validated, with speckled synaptophysin expression indicating worse outcome. CONCLUSIONS: Methylation subgrouping and CTNNB1 mutation status represent robust tools for the risk-stratification of medulloblastoma. A simple clinico-pathological risk score for “intermediate molecular risk” patients was identified, which deserves further validation. SECONDARY CATEGORY: Pediatrics.
doi:10.1093/neuonc/nou208.7
PMCID: PMC4144619
23.  Prognostic significance of clinical, histopathological, and molecular characteristics of medulloblastomas in the prospective HIT2000 multicenter clinical trial cohort 
Acta Neuropathologica  2014;128(1):137-149.
This study aimed to prospectively evaluate clinical, histopathological and molecular variables for outcome prediction in medulloblastoma patients. Patients from the HIT2000 cooperative clinical trial were prospectively enrolled based on the availability of sufficient tumor material and complete clinical information. This revealed a cohort of 184 patients (median age 7.6 years), which was randomly split at a 2:1 ratio into a training (n = 127), and a test (n = 57) dataset in order to build and test a risk score for this population. Independent validation was performed in a non-overlapping cohort (n = 83). All samples were subjected to thorough histopathological investigation, CTNNB1 mutation analysis, quantitative PCR, MLPA and FISH analyses for cytogenetic variables, and methylome analysis. By univariable analysis, clinical factors (M-stage), histopathological variables (large cell component, endothelial proliferation, synaptophysin pattern), and molecular features (chromosome 6q status, MYC amplification, subgrouping) were found to be prognostic. Molecular consensus subgrouping (WNT, SHH, Group 3, Group 4) was validated as an independent feature to stratify patients into different risk groups. When comparing methods for the identification of WNT-driven medulloblastoma, this study identified CTNNB1 sequencing and methylation profiling to most reliably identify these patients. After removing patients with particularly favorable (CTNNB1 mutation, extensive nodularity) or unfavorable (MYC amplification) markers, a risk score for the remaining “intermediate molecular risk” population dependent on age, M-stage, pattern of synaptophysin expression, and MYCN copy-number status was identified, with speckled synaptophysin expression indicating worse outcome. Test and independent validation of the score confirmed significant discrimination of patients by risk profile. Methylation subgrouping and CTNNB1 mutation status represent robust tools for the risk stratification of medulloblastoma. A simple clinico-pathological risk score was identified, which was confirmed in a test set and by independent clinical validation.
Electronic supplementary material
The online version of this article (doi:10.1007/s00401-014-1276-0) contains supplementary material, which is available to authorized users.
doi:10.1007/s00401-014-1276-0
PMCID: PMC4059991  PMID: 24791927
Medulloblastoma; Biomarker; Risk stratification; Prospective; Clinical trial cohort; Methylation profiling
24.  Recurrent somatic alterations of FGFR1 and NTRK2 in pilocytic astrocytoma 
Jones, David T.W. | Hutter, Barbara | Jäger, Natalie | Korshunov, Andrey | Kool, Marcel | Warnatz, Hans-Jörg | Zichner, Thomas | Lambert, Sally R. | Ryzhova, Marina | Quang, Dong Anh Khuong | Fontebasso, Adam M. | Stütz, Adrian M. | Hutter, Sonja | Zuckermann, Marc | Sturm, Dominik | Gronych, Jan | Lasitschka, Bärbel | Schmidt, Sabine | Şeker-Cin, Huriye | Witt, Hendrik | Sultan, Marc | Ralser, Meryem | Northcott, Paul A. | Hovestadt, Volker | Bender, Sebastian | Pfaff, Elke | Stark, Sebastian | Faury, Damien | Schwartzentruber, Jeremy | Majewski, Jacek | Weber, Ursula D. | Zapatka, Marc | Raeder, Benjamin | Schlesner, Matthias | Worth, Catherine L. | Bartholomae, Cynthia C. | von Kalle, Christof | Imbusch, Charles D. | Radomski, Sylwester | Lawerenz, Chris | van Sluis, Peter | Koster, Jan | Volckmann, Richard | Versteeg, Rogier | Lehrach, Hans | Monoranu, Camelia | Winkler, Beate | Unterberg, Andreas | Herold-Mende, Christel | Milde, Till | Kulozik, Andreas E. | Ebinger, Martin | Schuhmann, Martin U. | Cho, Yoon-Jae | Pomeroy, Scott L. | von Deimling, Andreas | Witt, Olaf | Taylor, Michael D. | Wolf, Stephan | Karajannis, Matthias A. | Eberhart, Charles G. | Scheurlen, Wolfram | Hasselblatt, Martin | Ligon, Keith L. | Kieran, Mark W. | Korbel, Jan O. | Yaspo, Marie-Laure | Brors, Benedikt | Felsberg, Jörg | Reifenberger, Guido | Collins, V. Peter | Jabado, Nada | Eils, Roland | Lichter, Peter | Pfister, Stefan M.
Nature genetics  2013;45(8):927-932.
Pilocytic astrocytoma, the most common childhood brain tumor1, is typically associated with mitogen-activated protein kinase (MAPK) pathway alterations2. Surgically inaccessible midline tumors are therapeutically challenging, showing sustained tendency for progression3 and often becoming a chronic disease with substantial morbidities4.
Here we describe whole-genome sequencing of 96 pilocytic astrocytomas, with matched RNA sequencing (n=73), conducted by the International Cancer Genome Consortium (ICGC) PedBrain Tumor Project. We identified recurrent activating mutations in FGFR1 and PTPN11 and novel NTRK2 fusion genes in non-cerebellar tumors. New BRAF activating changes were also observed. MAPK pathway alterations affected 100% of tumors analyzed, with no other significant mutations, indicating pilocytic astrocytoma as predominantly a single-pathway disease.
Notably, we identified the same FGFR1 mutations in a subset of H3F3A-mutated pediatric glioblastoma with additional alterations in NF15. Our findings thus identify new potential therapeutic targets in distinct subsets of pilocytic astrocytoma and childhood glioblastoma.
doi:10.1038/ng.2682
PMCID: PMC3951336  PMID: 23817572
25.  Integrative DNA methylation and gene expression analysis in high-grade soft tissue sarcomas 
Genome Biology  2013;14(12):r137.
Background
High-grade soft tissue sarcomas are a heterogeneous, complex group of aggressive malignant tumors showing mesenchymal differentiation. Recently, soft tissue sarcomas have increasingly been classified on the basis of underlying genetic alterations; however, the role of aberrant DNA methylation in these tumors is not well understood and, consequently, the usefulness of methylation-based classification is unclear.
Results
We used the Infinium HumanMethylation27 platform to profile DNA methylation in 80 primary, untreated high-grade soft tissue sarcomas, representing eight relevant subtypes, two non-neoplastic fat samples and 14 representative sarcoma cell lines. The primary samples were partitioned into seven stable clusters. A classification algorithm identified 216 CpG sites, mapping to 246 genes, showing different degrees of DNA methylation between these seven groups. The differences between the clusters were best represented by a set of eight CpG sites located in the genes SPEG, NNAT, FBLN2, PYROXD2, ZNF217, COL14A1, DMRT2 and CDKN2A. By integrating DNA methylation and mRNA expression data, we identified 27 genes showing negative and three genes showing positive correlation. Compared with non-neoplastic fat, NNAT showed DNA hypomethylation and inverse gene expression in myxoid liposarcomas, and DNA hypermethylation and inverse gene expression in dedifferentiated and pleomorphic liposarcomas. Recovery of NNAT in a hypermethylated myxoid liposarcoma cell line decreased cell migration and viability.
Conclusions
Our analysis represents the first comprehensive integration of DNA methylation and transcriptional data in primary high-grade soft tissue sarcomas. We propose novel biomarkers and genes relevant for pathogenesis, including NNAT as a potential tumor suppressor in myxoid liposarcomas.
doi:10.1186/gb-2013-14-12-r137
PMCID: PMC4054884  PMID: 24345474

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