Open AccessHigh INDO (indoleamine 2,3-dioxygenase) mRNA level in blasts of acute myeloid leukemic patients predicts poor clinical outcome
Author(s) -
Martine E.D. Chamuleau,
Arjan A. van de Loosdrecht,
Corine J. Hess,
Jeroen Janssen,
Adri Zevenbergen,
Ruud Delwel,
Peter J.M. Valk,
Bob Löwenberg,
Gert J. Ossenkoppele
Publication year - 2008
Publication title -
haematologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.782
H-Index - 142
eISSN - 1592-8721
pISSN - 0390-6078
DOI - 10.3324/haematol.13113
Subject(s) - indoleamine 2,3 dioxygenase , myeloid leukemia , myeloid , immune system , immunology , leukemia , acute leukemia , cancer research , biology , medicine , tryptophan , amino acid , genetics
Indoleamine 2,3-dioxygenase degrades the amino acid tryptophan which is essential for T cells. Tryptophan depletion causes T-cell cycle arrest and solid tumors that express high levels of indoleamine 2,3-dioxygenase can create immune suppression. Recently, blasts of patients with acute myeloid leukemia were shown to express indoleamine 2,3-dioxygenase. We determined INDO (encoding gene for indoleamine 2,3-dioxygenase) mRNA expression in leukemic blasts of 286 patients with acute myeloid leukemia by gene-expression profiling. Results were validated by quantitative polymerase chain reaction analysis in blasts of an independent cohort of 71 patients. High INDO expression was correlated to significantly shortened overall and relapse-free survival. Correlation of INDO expression to relevant known prognostic factors and survival identified high INDO expression as a strong negative independent predicting variable for overall and relapse-free survival. Inhibition of indoleamine 2,3-dioxygenase expressed by myeloid leukemic blasts may result in breaking immune tolerance and offers new therapeutic options for patients with acute myeloid leukemia.