TCRα rearrangements identify a subgroup of NKL-deregulated adult T-ALLs associated with favorable outcome

Leukemia. 2018 Jan;32(1):61-71. doi: 10.1038/leu.2017.176. Epub 2017 Jun 8.

Abstract

T-cell acute lymphoblastic leukemia (T-ALL) results from leukemic transformation of T-cell precursors arrested at specific differentiation stages, including an 'early-cortical' thymic maturation arrest characterized by expression of cytoplasmic TCRβ but no surface T-cell receptor (TCR) and frequent ectopic expression of the TLX1/3 NK-like homeotic proteins (NKL). We designed a TCRα VJC PCR to identify clonal TCRα rearrangements in 32% of 127 T-ALLs, including 0/52 immature/TCRγδ lineage cases and 41/75 (55%) TCRαβ lineage cases. Amongst the latter, TCRα rearrangements were not identified in 30/54 (56%) of IMβ/pre-αβ early-cortical T-ALLs, of which the majority (21/30) expressed TLX1/3. We reasoned that the remaining T-ALLs might express other NKL proteins, so compared transcript levels of 46 NKL in T-ALL and normal thymic subpopulations. Ectopic overexpression of 10 NKL genes, of which six are unreported in T-ALL (NKX2-3, BARHL1, BARX2, EMX2, LBX2 and MSX2), was detectable in 17/104 (16%) T-ALLs. Virtually all NKL overexpressing T-ALLs were TCRα unrearranged and ectopic NKL transcript expression strongly repressed Eα activity, suggesting that ectopic NKL expression is the major determinant in early-cortical thymic T-ALL maturation arrest. This immunogenetic T-ALL subtype, defined by TCRβ VDJ but no TCRα VJ rearrangement, is associated with a favorable outcome in GRAALL-treated adult T-ALLs.

Publication types

  • Clinical Trial, Phase II
  • Clinical Trial, Phase III
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Cell Differentiation / physiology
  • Cell Line, Tumor
  • Female
  • HeLa Cells
  • Homeodomain Proteins / metabolism*
  • Humans
  • Leukemia-Lymphoma, Adult T-Cell / metabolism*
  • Male
  • Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / metabolism*
  • Receptors, Antigen, T-Cell, alpha-beta / metabolism*
  • Receptors, Antigen, T-Cell, gamma-delta / metabolism*

Substances

  • Homeodomain Proteins
  • Receptors, Antigen, T-Cell, alpha-beta
  • Receptors, Antigen, T-Cell, gamma-delta