Genome-epigenome interplay in medulloblastoma


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Paul Northcott1
1St. Jude Children's Research Hospital

Abstract

The recent application of genomics to large series of primary human medulloblastomas has dramatically improved our perspective of the genes, pathways, and molecular processes underpinning this highly malignant paediatric brain tumour. Transcriptionally defined molecular subgroups have emerged, changing the fundamental definition of medulloblastoma from a single histologically recognised entity, to four distinct subtypes: WNT, SHH, Group3, and Group4. These subgroups exhibit highly discriminatory genomic landscapes, patient demographics, and clinical phenotypes. Next-generation sequencing has identified and implicated recurrently altered somatic drivers, many of which are affected in a subgroup-restricted manner. In contrast, somatic variants affecting chromatin-modifying genes, including histone ‘writers’, ‘erasers’, and ‘readers’ are prevalent in medulloblastoma and occur across subgroups, suggesting that deregulation of the epigenome is an essential step during medulloblastoma development. Integrative ‘omics’-based strategies have begun to dissect the fascinating genome-epigenome interplay underlying medulloblastoma, revealing previously undisclosed oncogenic mechanisms and drivers of disease. Furthermore, new insights into the biology and putative origins of the poorly understood Group3 and Group4 medulloblastomas have likewise been revealed. This talk will summarise these recent discoveries afforded through genomics and discuss their potential implications, both in the lab and in the clinic, going forward.