FLT3 Gene Mutation in Acute Myeloid Leukemia: Correlation with Hematological, Immunophenotypic, and Cytogenetic Characteristics

Abstract

\nIntroduction\u2003In acute myeloid leukemia (AML), FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) is a common driver mutation associated with high tumor burden and poor prognosis. This mutation is common in normal karyotype AML and such patients have high leukocyte count. The presence of this mutation can be predicted by certain hematological and immunophenotypic characteristics in day-to-day practice.\nObjective\u2003This study was undertaken to assess the strength of association between FLT3 gene mutation and hematological and immunophenotypic characteristics.\nMaterials and Methods\u2003Morphological, hematological, immunophenotypic, and cytogenetic characteristics of FLT3 mutations recorded in 424 patients of AML in adults and children between 2016 and 2019 in a tertiary care cancer center in Western India. Blasts were classified according to French-American-British method. Tumor burden was assessed by serum lactate dehydrogenase (LDH) levels, leucocyte count, and peripheral smear blast percentage.\nResults\u2003Out of 424 cases, FLT3-ITD and FLT3-tyrosine kinase domain mutation were found in 72 and 25 AML patients, respectively. Patients with FLT3 mutation had high tumor burden, characterized by high leukocyte count (p < 0.001), peripheral blood (p = 0.01) and bone marrow (p = 0.03) blast percentage, and high serum LDH (mean 777.8 vs. 586; p = 0.10) compared with FLT3-negative patients. They also featured high platelet count (p < 0.001). Morphological, immunophenotypic, and cytogenetic characteristics also have been presented in the study.\nConclusion\u2003Observations of the study suggest the presence of definitive hematological and immunophenotypic characteristics along with raised serum LDH levels serve as surrogate markers and indicators of FLT3 mutation in AML patients.