title: Distinct immunophenotype of early T-cell progenitors in T lymphoblastic leukemia/lymphoma may predict FMS-like tyrosine kinase 3 mutations.
abstract: FMS-like tyrosine kinase 3 (FLT3) mutation in T lymphoblastic leukemia/lymphoma (T-LL) is rare (∼4%) and reported only in cases with CD117 expression. This study aimed to identify the immunophenotypic features that may predict FLT3 mutations. We report 3 (43%) of 7 CD117(+) T-LL cases harboring FLT3-internal tandem duplication mutation. Compared with 4 FLT3-unmutated cases, all 3 FLT3-mutated cases had a distinct immunophenotype (CD1a(-)/CD2(+)/CD7(+)/CD34(+)/CD117(uniform+)/Tdt(+)) corresponding to the stage of earliest thymic T-cell progenitors possessing myeloid lineage potential. Indeed, all FLT3-mutated T-LL cases expressed myeloperoxidase on a very small subset of blasts and, thus, may be further considered a mixed phenotype acute leukemia, T/myeloid, by the 2008 World Health Organization classification scheme. We conclude that this unique immunophenotype (CD1a(-)/CD2(+)/CD7(+)/CD34(+)/CD117(+)/Tdt(+)) is a better predictor of FLT3 mutation than sole CD117 expression.
authors: Department of Pathology, University of Texas, Southwestern Medical Center at Dallas, 75235, USA.
authors: Charles M
authors: CM
authors: Zaremba
authors: Dwight
authors: D
authors: Oliver
authors: Maryellen
authors: M
authors: Cavalier
authors: Franklin
authors: F
authors: Fuda
authors: Nitin J
authors: NJ
authors: Karandikar
authors: Weina
authors: W
authors: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D008297:Male; D008875:Middle Aged; D009154:Mutation; D054218:Precursor T-Cell Lymphoblastic Leukemia-Lymphoma / Q000145:classification / Q000235:genetics* / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D051941:fms-Like Tyrosine Kinase 3 / Q000235:genetics*
chemical_list: C497970:FLT3 protein, human; D051941:fms-Like Tyrosine Kinase 3