Determination of FLT3 mutations and minimal residual deasease monitoring in FLT3-positive acute myeloid leukemia

Introduction. The identification of mutations in the FLT3 gene is essential for the diagnosis, prognosis, and selection of treatment strategies for acute myeloid leukemia (AML).

Aim: to compare the main methods used in the diagnosis of FLT3 mutations in patients with AML.

Materials and methods. Identification of FLT3 gene mutations was carried out using polymerase chain reaction (PCR) with fragment analysis (PCR-FA), double-label PCR-FA, tandem duplication method (TD-PCR), next-generation sequencing (NGS), and allele-specific PCR (AS-PCR) in patients who were diagnosed or observed with AML at the National Medical Research Center for Hematology from 2017 to 01.06.2024.

Results. The PCR-FA method showed reliable results in the testing of internal tandem duplications of FLT3 gene (FLT3-ITD). The double-label PCR-FA method had greater sensitivity and specificity that allowed detection of FLT3-ITD in a larger number of patients. TD-PCR was useful for determining minimal residual disease (MRD) in some patients. NGS provided information about the site of ITD insertion and its nucleotide composition, but also expanded our understanding of point mutations in the first and second tyrosine kinase (TKD1 and TKD2) domains, which may cause resistance to tyrosine kinase inhibitors.

Conclusion. The use of several methods to analyze FLT3 mutations makes it possible to make a more accurate identification of minor FLT3-ITD clones, as well as the detection of MRD and somatic point mutations within the TKD1 and TKD2 domains. Recommendations are given on the molecular genetic diagnosis of FLT3 mutations in AML.

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