Frequent cases of RAS-mutated Down syndrome acute lymphoblastic leukaemia lack JAK2 mutations

Nat Commun. 2014 Aug 8:5:4654. doi: 10.1038/ncomms5654.

Abstract

Children with Down syndrome (DS) and acute lymphoblastic leukaemia (ALL) have poorer survival and more relapses than non-DS children with ALL, highlighting an urgent need for deeper mechanistic understanding of DS-ALL. Here, using full-exome or cancer genes-targeted sequencing of 42 ALL samples from 39 DS patients, we uncover driver mutations in RAS, (KRAS and NRAS) recurring to a similar extent (15/42) as JAK2 (12/42) mutations or P2RY8-CRLF2 fusions (14/42). RAS mutations are almost completely mutually exclusive with JAK2 mutations (P=0.016), driving a combined total of two-thirds of analysed cases. Clonal architecture analysis reveals that both RAS and JAK2 drove sub-clonal expansions primarily initiated by CRLF2 rearrangements, and/or mutations in chromatin remodellers and lymphocyte differentiation factors. Remarkably, in 2/3 relapsed cases, there is a switch from a primary JAK2- or PTPN11-mutated sub-clone to a RAS-mutated sub-clone in relapse. These results provide important new insights informing the patient stratification strategies for targeted therapeutic approaches for DS-ALL.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Child
  • Chromatin / chemistry
  • DNA Mutational Analysis
  • Down Syndrome / genetics*
  • Down Syndrome / metabolism
  • Female
  • Gene Deletion
  • Gene Expression Regulation, Leukemic
  • Humans
  • Janus Kinase 2 / genetics*
  • Lymphocytes / cytology
  • Male
  • Mutation*
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / genetics*
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / metabolism
  • Receptors, Cytokine / genetics
  • ras Proteins / metabolism*

Substances

  • CRLF2 protein, human
  • Chromatin
  • Receptors, Cytokine
  • JAK2 protein, human
  • Janus Kinase 2
  • ras Proteins

Associated data

  • SRA/SRP044903