Targetable kinase gene fusions in high-risk B-ALL: a study from the Children's Oncology Group

Blood. 2017 Jun 22;129(25):3352-3361. doi: 10.1182/blood-2016-12-758979. Epub 2017 Apr 13.

Abstract

Philadelphia chromosome-like (Ph-like) acute lymphoblastic leukemia (ALL) is a high-risk subtype characterized by genomic alterations that activate cytokine receptor and kinase signaling. We examined the frequency and spectrum of targetable genetic lesions in a retrospective cohort of 1389 consecutively diagnosed patients with childhood B-lineage ALL with high-risk clinical features and/or elevated minimal residual disease at the end of remission induction therapy. The Ph-like gene expression profile was identified in 341 of 1389 patients, 57 of whom were excluded from additional analyses because of the presence of BCR-ABL1 (n = 46) or ETV6-RUNX1 (n = 11). Among the remaining 284 patients (20.4%), overexpression and rearrangement of CRLF2 (IGH-CRLF2 or P2RY8-CRLF2) were identified in 124 (43.7%), with concomitant genomic alterations activating the JAK-STAT pathway (JAK1, JAK2, IL7R) identified in 63 patients (50.8% of those with CRLF2 rearrangement). Among the remaining patients, using reverse transcriptase polymerase chain reaction or transcriptome sequencing, we identified targetable ABL-class fusions (ABL1, ABL2, CSF1R, and PDGFRB) in 14.1%, EPOR rearrangements or JAK2 fusions in 8.8%, alterations activating other JAK-STAT signaling genes (IL7R, SH2B3, JAK1) in 6.3% or other kinases (FLT3, NTRK3, LYN) in 4.6%, and mutations involving the Ras pathway (KRAS, NRAS, NF1, PTPN11) in 6% of those with Ph-like ALL. We identified 8 new rearrangement partners for 4 kinase genes previously reported to be rearranged in Ph-like ALL. The current findings provide support for the precision-medicine testing and treatment approach for Ph-like ALL implemented in Children's Oncology Group ALL trials.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural

MeSH terms

  • Child
  • Female
  • Fusion Proteins, bcr-abl / genetics
  • Gene Expression Regulation, Leukemic
  • Gene Fusion*
  • Humans
  • Interleukin-7 Receptor alpha Subunit / genetics
  • Janus Kinase 2 / genetics
  • Male
  • Mutation
  • Philadelphia Chromosome
  • Precursor B-Cell Lymphoblastic Leukemia-Lymphoma / genetics*
  • Protein Kinases / genetics*
  • Receptors, Cytokine / genetics
  • Retrospective Studies
  • Transcriptome

Substances

  • CRLF2 protein, human
  • IL7R protein, human
  • Interleukin-7 Receptor alpha Subunit
  • Receptors, Cytokine
  • Protein Kinases
  • Fusion Proteins, bcr-abl
  • JAK2 protein, human
  • Janus Kinase 2