In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 30, No. 15_suppl ( 2012-05-20), p. 9518-9518
Abstract:
9518 Background: Medulloblastoma is a malignant childhood brain tumor comprising four discrete subgroups (SHH-subgroup, WNT-subgroup, subgroup-3 and subgroup-4). The genetic alterations that drive these subgroups and that might serve as treatment targets are largely unknown. Methods: We sequenced entire genomes of 37 tumors and matched normal blood. 136 somatically mutated genes identified in this discovery cohort were sequenced in an additional 56 medulloblastomas. All tumors were classified into the 4 subgroups by expression profiling and immunohistochemistry. All mutations were validated by custom capture, 454, or Sanger sequencing. Results: Recurrent mutations were detected in 49 genes: 41 are not yet implicated in medulloblastoma. Several target distinct components of the epigenetic machinery in different disease subgroups, e.g., regulators of H3K27 and H3K4 trimethylation in subgroup-3 and 4 (e.g., KDM6A and ZMYM3), and CTNNB1-associated chromatin remodellers in WNT-subgroup tumors (e.g., SMARCA4 and CREBBP). Modelling of mutations in mouse lower rhombic lip progenitors that generate WNT-subgroup tumours, identified genes that maintain this cell lineage (DDX3X) as well as mutated genes that initiate (CDH1) or cooperate (PIK3CA) in tumourigenesis. Conclusions: We have identified several new recurrent somatic mutations that are enriched in specific subgroups of medulloblastoma. Alterations affecting subgroup-3 and 4 tumors appear to disrupt chromatin marking, most notably H3K27me 3 , potentially preserving a stem cell-like state in tumor cells. Mutations in WNT subgroup tumors affect binding partners of CTNNB1 that regulate WNT-response gene transcription. These data provide important new insights into the pathogenesis of medulloblastoma subgroups and highlight targets for therapeutic development.
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/jco.2012.30.15_suppl.9518
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2012
detail.hit.zdb_id:
2005181-5
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