An activating intragenic deletion in NOTCH1 in human T-ALL

Blood. 2012 May 31;119(22):5211-4. doi: 10.1182/blood-2011-10-388504. Epub 2012 Apr 17.


Oncogenic activating mutations in NOTCH1 occur in more than 50% of T-cell acute lymphoblastic leukemias (T-ALLs). In the present study, we describe a novel mechanism of NOTCH1 activation in T-ALL in which a deletion removing the 5' portion of NOTCH1 abolishes the negative regulatory control of the extracellular domain and leads to constitutively active NOTCH1 signaling. Polypeptides translated from truncated transcripts encoded by the NOTCH1 deletion allele retain the transmembrane domain of the receptor and are constitutively cleaved by the γ-secretase complex, resulting in high levels of NOTCH1 signaling that can be effectively blocked by γ-secretase inhibitors. Our results expand the spectrum of oncogenic lesions activating NOTCH1 signaling in human T-ALL.

Publication types

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

MeSH terms

  • Adult
  • Alleles*
  • Female
  • Humans
  • Male
  • Neoplasm Proteins / genetics*
  • Neoplasm Proteins / metabolism
  • Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / genetics*
  • Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / metabolism
  • Protein Structure, Tertiary
  • Receptor, Notch1 / genetics*
  • Receptor, Notch1 / metabolism
  • Sequence Deletion
  • Signal Transduction / genetics*


  • NOTCH1 protein, human
  • Neoplasm Proteins
  • Receptor, Notch1