Genome Sequencing of Pediatric Medulloblastoma Links Catastrophic DNA Rearrangements with TP53 Mutations
A partir du séquençage du génome tumoral d'un patient atteint d'un médulloblastome Sonic-Hedgehog et présentant une mutation germinale du gène TP53, puis du séquençage de divers autres génomes tumoraux, notamment de patients atteints d'une leucémie myéloïde aiguë, cette étude identifie une association entre des mutations du gène p53 et des réarrangements massifs de l'ADN
Genomic rearrangements are thought to occur progressively during tumor development. Recent findings, however, suggest an alternative mechanism, involving massive chromosome rearrangements in a one-step catastrophic event termed chromothripsis. We report the whole-genome sequencing-based analysis of a Sonic-Hedgehog medulloblastoma (SHH-MB) brain tumor from a patient with a germline TP53 mutation (Li-Fraumeni syndrome), uncovering massive, complex chromosome rearrangements. Integrating TP53 status with microarray and deep sequencing-based DNA rearrangement data in additional patients reveals a striking association between TP53 mutation and chromothripsis in SHH-MBs. Analysis of additional tumor entities substantiates a link between TP53 mutation and chromothripsis, and indicates a context-specific role for p53 in catastrophic DNA rearrangements. Among these, we observed a strong association between somatic TP53 mutations and chromothripsis in acute myeloid leukemia. These findings connect p53 status and chromothripsis in specific tumor types, providing a genetic basis for understanding particularly aggressive subtypes of cancer. º Complex chromosomal alterations (chromothripsis) observed in medulloblastomas º Cancers with such alterations harbor TP53 mutations º Context-specific link between the status of p53 and likelihood of chromothripsis º p53 status and chromothripsis also correlate with aggressive acute myeloid leukemia Connecting p53 status and chromothripsis in specific types of cancer provides a genetic basis for the more aggressive forms of medulloblastoma and leukemia.