Global analysis of the medulloblastoma epigenome identifies disease-subgroup-specific inactivation of COL1A2

Jennifer Anderton; Dr Janet Lindsey; Dr Meryl Lusher; Dr Richard Gilbertson; Professor Simon Bailey; Professor David Ellison; Professor Steven Clifford

Global analysis of the medulloblastoma epigenome identifies disease-subgroup-specific inactivation of COL1A2 Lookup NU author(s) Jennifer Anderton Dr Janet Lindsey Dr Meryl Lusher Dr Richard Gilbertson Professor Simon Bailey Professor David Ellison Professor Steven Clifford



Author(s)		Anderton JA, Lindsey JC, Lusher ME, Gilbertson RJ, Bailey S, Ellison DW, Clifford SC
Publication type		Article
Journal		Neuro-oncology
Year		2008
Volume		10
Issue		6
Pages		981-994
ISSN (print)		1522-8517
ISSN (electronic)		1523-5866



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Candidate gene investigations have indicated a significant role for epigenetic events in the pathogenesis of medulloblastoma, the most common malignant brain tumor of childhood. To assess the medulloblastoma epigenome more comprehensively, we undertook a genomewide investigation to identify genes that display evidence of methylation-dependent regulation. Expression microarray analysis of medulloblastoma cell lines following treatment with a DNA methyltransferase inhibitor revealed deregulation of multiple transcripts (3%-6% of probes per cell line). Eighteen independent genes demonstrated >3-fold reactivation in all cell lines tested. Bisulfite sequence analysis revealed dense CpG island methylation associated with transcriptional silencing for 12 of these genes. Extension of this analysis to primary tumors and the normal cerebellum revealed three major classes of epigenetically regulated genes: (1) normally methylated genes (DAZL, ZNF157, ASN) whose methylation reflects somatic patterns observed in the cerebellum, (2) X-linked genes (MSN, POU3F4, HTR2C) that show disruption of their sex-specific methylation patterns in tumors, and (3) tumor-specific methylated genes (COL1A2, S100A10, S100A6, HTATIP2, CDH1, LXN) that display enhanced methylation levels in tumors compared with the cerebellum. Detailed analysis of COL1A2 supports a key role in medulloblastoma tumorigenesis; dense biallelic methylation associated with transcriptional silencing was observed in 46 of 60 cases (77%). Moreover, COL1A2 status distinguished infant medulloblastomas of the desmoplastic histopathological subtype, indicating that distinct molecular pathogenesis may underlie these tumors and their more favorable prognosis. These data reveal a more diverse and expansive medulloblastoma epi genome than previously understood and provide strong evidence that the methylation status of specific genes may contribute to the biological subclassification of medulloblastoma.



Publisher		Oxford University Press
URL		http://dx.doi.org/10.1215/15228517-2008-048
DOI		10.1215/15228517-2008-048
PubMed id		18664619

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