Cytogenetic and FMS-like tyrosine kinase 3 mutation analyses in acute promyelocytic leukemia patients

ABSTRACT

The secondary genetic changes other than the promyelocytic leukemia-retinoic acid receptor [PML-RARA] fusion gene may contribute to the acute promyelocytic leukemogenesis. Chromosomal alterations and mutation of FLT3 [FMS-like tyrosine kinase 3] tyrosine kinase receptor are the frequent genetic alterations in acute myeloid leukemia. However, the prognostic significance of FLT3 mutations in acute promyelocytic leukemia [APL] is not firmly established. In this study, the chromosomal abnormalities were analyzed by bone marrow cytogenetic in 45 APL patients and FLT3 internal tandem duplications [ITD] screening by fragment length analysis and FLT3 D835 mutation by melting curve analysis were screened in 23 APL samples. Cytogenetic study showed 14.3% trisomy 8 and 17.1% chromosomal abnormalities other than t[15;17]. About 13% of the patients had FLT3 ITD, and 26% had D835 point mutation. FLT3 ITD mutation was associated with higher white blood cell count at presentation and poor prognosis. The PML-RARA translocation alone may not be sufficient to induce leukemia. Therefore, we assume that FLT3 mutations and the other genetic and chromosomal alterations may cooperate with PML-RARA in the development of APL disease