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  • Germany  (13)
  • Jun  (10)
  • MUTATIONS  (10)
  • MYC  (7)
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  • 1
    Keywords: brain ; tumor ; Germany ; neoplasms ; TOOL ; HYBRIDIZATION ; DIFFERENTIATION ; TUMORS ; MARKER ; BIOLOGY ; IN-SITU ; AMPLIFICATION ; AGE ; ABERRATIONS ; FISH ; CENTRAL-NERVOUS-SYSTEM ; pathology ; CHILDREN ; BEHAVIOR ; CHROMOSOMES ; FEATURES ; brain tumor ; BRAIN-TUMORS ; PRIMITIVE NEUROECTODERMAL TUMORS ; LOCUS ; diagnostic marker ; ABUNDANT NEUROPIL ; TRUE ROSETTES ; 19q13 ; Embryonal brain tumor ; Ependymoblastoma ; ETANTR ; Molecular diagnosis ; WHO classification of CNS tumors
    Abstract: Ependymoblastoma (EBL) and embryonal tumor with abundant neuropil and true rosettes (ETANTR) are very aggressive embryonal neoplasms characterized by the presence of ependymoblastic multilayered rosettes typically occurring in children below 6 years of age. It has not been established whether these two tumors really comprise distinct entities. Earlier, using array-CGH, we identified a unique focal amplification at 19q13.42 in a case of ETANTR. In the present study, we investigated this locus by fluorescence in situ hybridization in 41 tumors, which had morphologically been diagnosed as EBL or ETANTR. Strikingly, FISH analysis revealed 19q13.42 amplifications in 37/40 samples (93%). Among tumors harboring the amplification, 19 samples were identified as ETANTR and 18 as EBL. The three remaining tumors showed a polysomy of chromosome 19. Analysis of recurrent/metastatic tumors (n = 7) showed that the proportion of nuclei carrying the amplification was increased (up to 80-100% of nuclei) in comparison to the corresponding primary tumors. In conclusion, we have identified a hallmark cytogenetic aberration occurring in virtually all embryonal brain tumors with ependymoblastic rosettes suggesting that ETANTR and EBL comprise a single biological entity. FISH analysis of the 19q13.42 locus is a very promising diagnostic tool to identify a subset of primitive neuroectodermal tumors with distinct morphology, biology, and clinical behavior
    Type of Publication: Journal article published
    PubMed ID: 20407781
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  • 2
    Keywords: brain ; tumor ; Germany ; MODEL ; MODELS ; ALGORITHM ; screening ; SYSTEM ; COHORT ; RISK ; HYBRIDIZATION ; TUMORS ; PATIENT ; ACTIVATION ; DNA ; MARKER ; IMPACT ; prognosis ; BIOLOGY ; DELETION ; IN-SITU ; AMPLIFICATION ; COMPARATIVE GENOMIC HYBRIDIZATION ; NUMBER ; ABERRATIONS ; MARKERS ; ONCOGENE ; beta-catenin ; PROGNOSTIC VALUE ; OUTCOMES ; CHILDREN ; ONCOLOGY ; ADULT ; ADULTS ; CHILDHOOD ; brain tumor ; GENOMIC ABERRATIONS ; DNA COPY NUMBER ; medulloblastoma ; methods ; PROGNOSTIC MARKER ; RISK STRATIFICATION ; LOCI ; MYC ; outcome ; TUMOR BIOLOGY ; Genetic ; NUCLEAR BETA-CATENIN ; clinical oncology ; STRATIFICATION
    Abstract: Purpose Medulloblastoma (MB) is the most common malignant brain tumor in children, whereas it rarely presents in adults. We aimed to identify genetic aberrations in 146 adult MBs to evaluate age-dependent differences in tumor biology and adapt age-specific risk stratification models. Methods As a screening set, we studied a cohort of 34 adult MBs by using array-based comparative genomic hybridization comparing molecular results with clinical data. DNA copy number aberrations identified as possible prognostic markers were validated in an independent cohort of 112 adult patients with MB by fluorescent in situ hybridization analysis. Results were compared with the data obtained from 404 pediatric patients with MB. Results CDK6 amplification, 10q loss, and 17q gain are the most powerful prognostic markers in adult MB. Whereas MYC/MYCN oncogene amplifications had a high prognostic value in pediatric MB, these aberrations were rarely observed in adult tumors. Surprisingly, adult MBs with 6q deletion and nuclear beta-catenin activation did not share the excellent prognosis with their pediatric counterparts. Conclusion Adult MB is distinct from pediatric MB in terms of genomic aberrations and their impact on clinical outcomes. Therefore, adult MBs require age-specific risk stratification models. We propose a molecular staging system involving three distinct risk groups based on DNA copy number status of 10q and 17q
    Type of Publication: Journal article published
    PubMed ID: 20479417
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  • 3
    Keywords: PATHWAY ; ACTIVATION ; MUTATIONS ; BRAF ; IDH1 ; Diffuse astrocytoma ; IDH2 ; Pilocytic astrocytoma
    Abstract: Separation of pilocytic astrocytoma from diffuse astrocytomas frequently poses problems mostly related to small sample size. Precise classification and grading are essential due to different therapeutic strategies prompted by diagnoses of pilocytic astrocytoma WHO grade I, diffuse astrocytomas WHO grade II or anaplastic astrocytoma WHO grade III. Recently, genomic aberrations with a high specificity for distinct glioma entities have been described. Pilocytic astrocytomas carry a duplication at chromosome band 7q34 containing a BRAF-KIAA1549 gene fusion in the majority of cases. IDH1 mutations are observed very frequently in adult astrocytomas and IDH2 mutations have been reported in some astrocytomas. We examined a series of 120 astrocytomas including 70 pilocytic astrocytomas WHO grade I and 50 diffuse astrocytomas WHO grade II for both, BRAF-KIAA1549 fusion with a newly developed FISH assay and mutations in IDH1 and IDH2 by direct sequencing. Pilocytic astrocytomas contained the BRAF fusion in 49 cases (70%) but neither IDH1 nor IDH2 mutations. Astrocytomas WHO grade II exhibited IDH1 mutations in 38 cases (76%) but neither IDH2 mutations nor BRAF fusions. Thus, combined molecular analysis of BRAF and IDH1 is a sensitive and highly specific approach to separate pilocytic astrocytoma from diffuse astrocytoma.
    Type of Publication: Journal article published
    PubMed ID: 19543740
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  • 4
    Keywords: CANCER ; EXPRESSION ; SURVIVAL ; GENES ; PROTEIN ; transcription ; TRANSCRIPTION FACTOR ; IDENTIFICATION ; PROMOTER ; chemotherapy ; MUTATIONS ; LOCALIZATION ; METHYLATION ; BRAIN-TUMORS ; ACUTE MYELOID-LEUKEMIA ; INTRACRANIAL EPENDYMOMAS ; MDS1/EVI1
    Abstract: Purpose: Ependymomas are glial tumors of presumably radial glial origin that share morphologic similarities with ependymal cells. The molecular genetics of ependymomas of supratentorial, infratentorial, and spinal location is heterogeneous. We aimed at identifying pathways operative in the development of infratentorial ependymomas. Experimental Design: To do so, gene expression profiles of tumor cells laser microdissected from infratentorial ependymomas (n = 15) were compared with that of nonneoplastic ependymal cells laser microdissected from autopsy tissue (n = 7). Results: Among 31 genes significantly overexpressed (〉5-fold) in ependymomas, transcription factor EVI1 (ecotropic viral integration site 1) showed the highest overexpression (35-fold). Evi-1 protein expression could be confirmed in formalin-fixed, paraffin-embedded samples of 26 of 28 infratentorial ependymomas but only in 7 of 47 nonependymal glial tumors (P 〈 0.001). Furthermore, MDS1/EVI1 fusion transcripts were detectable in 17 of 28 infratentorial ependymomas and significantly correlated with MGMT (O6-methylguanine-DNA-methyltransferase) promoter hypermethylation (P 〈 0.05). In primary infratentorial ependymoma cells, transfection with EVI1-specific siRNAs resulted in significant growth inhibition [48 hours: 87% +/- 2% and 74% +/- 10% as compared with control (mean +/- SD; P 〈 0.001)]. The prognostic role of EVI1 could further be validated in an independent cohort of 39 infratentorial and 26 supratentorial ependymomas on the basis of mRNA expression profiling. Although in supratentorial ependymomas EVI1 expression status had no prognostic impact, in infratentorial ependymomas, high EVI1 expression was associated with shorter overall survival and progression-free survival. Conclusions: To conclude, the transcription factor Evi-1 is overexpressed in infratentorial ependymomas, promotes proliferation of ependymal tumor cells, and is prognostically unfavorable.
    Type of Publication: Journal article published
    PubMed ID: 21493867
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  • 5
    Keywords: CANCER ; PATHWAY ; GENES ; ACTIVATION ; MUTATIONS ; SUBGROUPS ; LANDSCAPE ; TETRAPLOID TUMOR-CELLS ; TBR1
    Abstract: Medulloblastoma is an aggressively growing tumour, arising in the cerebellum or medulla/brain stem. It is the most common malignant brain tumour in children, and shows tremendous biological and clinical heterogeneity. Despite recent treatment advances, approximately 40% of children experience tumour recurrence, and 30% will die from their disease. Those who survive often have a significantly reduced quality of life. Four tumour subgroups with distinct clinical, biological and genetic profiles are currently identified. WNT tumours, showing activated wingless pathway signalling, carry a favourable prognosis under current treatment regimens. SHH tumours show hedgehog pathway activation, and have an intermediate prognosis. Group 3 and 4 tumours are molecularly less well characterized, and also present the greatest clinical challenges. The full repertoire of genetic events driving this distinction, however, remains unclear. Here we describe an integrative deep-sequencing analysis of 125 tumour-normal pairs, conducted as part of the International Cancer Genome Consortium (ICGC) PedBrain Tumor Project. Tetraploidy was identified as a frequent early event in Group 3 and 4 tumours, and a positive correlation between patient age and mutation rate was observed. Several recurrent mutations were identified, both in known medulloblastoma-related genes (CTNNB1, PTCH1, MLL2, SMARCA4) and in genes not previously linked to this tumour (DDX3X, CTDNEP1, KDM6A, TBR1), often in subgroup-specific patterns. RNA sequencing confirmed these alterations, and revealed the expression of what are, to our knowledge, the first medulloblastoma fusion genes identified. Chromatin modifiers were frequently altered across all subgroups. These findings enhance our understanding of the genomic complexity and heterogeneity underlying medulloblastoma, and provide several potential targets for new therapeutics, especially for Group 3 and 4 patients.
    Type of Publication: Journal article published
    PubMed ID: 22832583
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  • 6
    Keywords: GENE ; NF-KAPPA-B ; MUTATIONS ; CENTRAL-NERVOUS-SYSTEM ; medulloblastoma ; SUBGROUPS ; GLIOBLASTOMA ; CHILDHOOD EPENDYMOMAS ; PEDIATRIC INTRACRANIAL EPENDYMOMAS ; POSTERIOR-FOSSA EPENDYMOMAS
    Abstract: 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.
    Type of Publication: Journal article published
    PubMed ID: 25965575
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  • 7
    Keywords: GROWTH ; TUMORS ; MUTATIONS ; CENTRAL-NERVOUS-SYSTEM ; PYRUVATE-KINASE
    Abstract: PURPOSE: Myxopapillary ependymoma (MPE) is a distinct histologic variant of ependymoma arising commonly in the spinal cord. Despite an overall favorable prognosis, distant metastases, subarachnoid dissemination, and late recurrences have been reported. Currently, the only effective treatment for MPE is gross-total resection. We characterized the genomic and transcriptional landscape of spinal ependymomas in an effort to delineate the genetic basis of this disease and identify new leads for therapy. EXPERIMENTAL DESIGN: Gene expression profiling was performed on 35 spinal ependymomas, and copy number profiling was done on an overlapping cohort of 46 spinal ependymomas. Functional validation experiments were performed on tumor lysates consisting of assays measuring pyruvate kinase M activity (PKM), hexokinase activity (HK), and lactate production. RESULTS: At a gene expression level, we demonstrate that spinal grade II and MPE are molecularly and biologically distinct. These are supported by specific copy number alterations occurring in each histologic variant. Pathway analysis revealed that MPE are characterized by increased cellular metabolism, associated with upregulation of HIF1alpha. These findings were validated by Western blot analysis demonstrating increased protein expression of HIF1alpha, HK2, PDK1, and phosphorylation of PDHE1A. Functional assays were performed on MPE lysates, which demonstrated decreased PKM activity, increased HK activity, and elevated lactate production. CONCLUSIONS: Our findings suggest that MPE may be driven by a Warburg metabolic phenotype. The key enzymes promoting the Warburg phenotype: HK2, PKM2, and PDK are targetable by small-molecule inhibitors/activators, and should be considered for evaluation in future clinical trials for MPE. Clin Cancer Res; 21(16); 3750-8. (c)2015 AACR.
    Type of Publication: Journal article published
    PubMed ID: 25957288
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  • 8
    Keywords: INHIBITOR ; Germany ; DISEASE ; RISK ; SITE ; GENE ; GENES ; PROTEIN ; ACTIVATION ; CLEAVAGE ; MUTATION ; genetics ; MUTATIONS ; Jun ; INDIVIDUALS ; heredity ; chronic pancreatitis ; RECOMBINANT ; pancreas ; VARIANT ; ENZYME ; pancreatic ; LOSSES ; odds ratio ; PROTECTS ; HEREDITARY PANCREATITIS ; HUMAN CATIONIC TRYPSINOGEN
    Abstract: Chronic pancreatitis is a common inflammatory disease of the pancreas. Mutations in the genes encoding cationic trypsinogen (PRSS1) 1 and the pancreatic secretory trypsin inhibitor (SPINK1) 2 are associated with chronic pancreatitis. Because increased proteolytic activity owing to mutated PRSS1 enhances the risk for chronic pancreatitis, mutations in the gene encoding anionic trypsinogen (PRSS2) may also predispose to disease. Here we analyzed PRSS2 in individuals with chronic pancreatitis and controls and found, to our surprise, that a variant of codon 191 (G191R) is overrepresented in control subjects: G191R was present in 220/6,459 (3.4%) controls but in only 32/2,466 (1.3%) affected individuals (odds ratio 0.37; P = 1.1 x 10(-8)). Upon activation by enterokinase or trypsin, purified recombinant G191R protein showed a complete loss of trypsin activity owing to the introduction of a new tryptic cleavage site that renders the enzyme hypersensitive to autocatalytic proteolysis. In conclusion, the G191R variant of PRSS2 mitigates intrapancreatic trypsin activity and thereby protects against chronic pancreatitis
    Type of Publication: Journal article published
    PubMed ID: 16699518
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  • 9
    Keywords: EXPRESSION ; COHORT ; DISEASE ; TISSUE ; IDENTIFICATION ; COMPARATIVE GENOMIC HYBRIDIZATION ; chemotherapy ; MUTATIONS ; ABNORMALITIES ; CHILDREN ; IMBALANCES ; PEDIATRIC EPENDYMOMA ; INTRACRANIAL EPENDYMOMA ; CLASS DISCOVERY
    Abstract: Despite the histological similarity of ependymomas from throughout the neuroaxis, the disease likely comprises multiple independent entities, each with a distinct molecular pathogenesis. Transcriptional profiling of two large independent cohorts of ependymoma reveals the existence of two demographically, transcriptionally, genetically, and clinically distinct groups of posterior fossa (PF) ependymomas. Group A patients are younger, have laterally located tumors with a balanced genome, and are much more likely to exhibit recurrence, metastasis at recurrence, and death compared with Group B patients. Identification and optimization of immunohistochennical (IHC) markers for PF ependymoma subgroups allowed validation of our findings on a third independent cohort, using a human ependymonna tissue microarray, and provides a tool for prospective prognostication and stratification of PF ependymoma patients
    Type of Publication: Journal article published
    PubMed ID: 21840481
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  • 10
    Keywords: EXPRESSION ; PATHWAY ; DISEASE ; DISTINCT ; GENE-EXPRESSION ; TUMORS ; prognosis ; MARKERS ; PRECURSORS ; MYCN ; N-MYC ; medulloblastoma ; CHILDHOOD MEDULLOBLASTOMA ; RISK STRATIFICATION ; MYC ; STRATIFICATION ; PEDIATRIC MEDULLOBLASTOMAS ; SHH pathway ; 10q loss ; MATRIX FACTORIZATION ; MULTICENTER TRIAL HIT91 ; SHH
    Abstract: Focal high-level amplifications of MYC (or MYCC) define a subset of high-risk medulloblastoma patients. However, the prognostic role of MYCN oncogene amplification remains unresolved. We aimed to evaluate the prognostic value of this alteration alone and in combination with biological modifiers in 67 pediatric medulloblastomas with MYCN amplification (MYCN-MB). Twenty-one MYCN-MB were examined using gene expression profiling and array-CGH, whereas for 46 tumors immunohistochemical analysis and FISH were performed. All 67 tumors were further subjected to mutational analyses. We compared molecular, clinical, and prognostic characteristics both within biological MYCN-MB groups and with non-amplified tumors. Transcriptomic analysis revealed SHH-driven tumorigenesis in a subset of MYCN-MBs indicating a biological dichotomy of MYCN-MB. Activation of SHH was accompanied by variant-specific cytogenetic aberrations including deletion of 9q in SHH tumors. Non-SHH MB were associated with gain of 7q and isochromosome 17q/17q gain. Among clinically relevant variables, SHH subtype and 10q loss for non-SHH tumors comprised the most powerful markers of favorable prognosis in MYCN-MB. In conclusion, we demonstrate considerable heterogeneity within MYCN-MB in terms of genetics, tumor biology, and clinical outcome. Thus, assessment of disease group and 10q copy-number status may improve risk stratification of this group and may delineate MYCN-MB with the same dismal prognosis as MYC amplified tumors. Furthermore, based on the enrichment of MYCN and GLI2 amplifications in SHH-driven medulloblastoma, amplification of these downstream signaling intermediates should be taken into account before a patient is enrolled into a clinical trial using a smoothened inhibitor
    Type of Publication: Journal article published
    PubMed ID: 22160402
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