Investigation of FMS-Like Tyrosine Kinase 3 Mutation Frequency in Myelodysplastic Syndrome

Introduction: FMS-Like Tyrosine Kinase Class 3 (FLT3) mutations harbor poor prognosis, high relapse, and decreased overall survival in acute myeloblastic leukemia (AML). This mutation is also known to be demonstrated in myelodysplastic syndrome (MDS), chronic myelomonocytic leukemia and acute lymphoblastic leukemia. This study included 94 MDS-diagnosed patients and we tried to investigate FLT3 mutation frequency (as tyrosine kinase domain-TKD and internal tandem duplication-ITD).

Materials and Methods: Polymerase chain reaction (PCR), restriction fragment length polymorphism, and agarose-gel electrophoresis methods were used to analyze the mutation. The blood samples were collected in K3-EDTA tubes, and total DNA was isolated using genomic DNA isolation kits (GeneMark, Cat No: DP023P). For the detection of FLT3-ITD mutation, PCR was performed to amplify a 330- base pair fragment of exons 11 and 12 of FLT3 using FAM (Carboxyfluorescein)-labeled ITD-11F and HEX (Hexachloro-Fluorescein )-labeled ITD-12R primers in a thermal cycler (Eppendorf). Similarly, to detect D835 mutation, a 115- bp region of exon 17 of the FLT3 gene region was amplified using primers.

Results: One patient was found FLT3-ITD positive (1.1%). The patient was 64-year-old and diagnosed with MDS-excess blast type 2 according to the World Health Organisation 2016 myeloid neoplasm classification. He transformed to AML within 19 months and subsequently died after 1 month. No patient with tyrosine kinase domain mutation was detected.

Conclusion: FLT3 mutation is considered a significant parameter to define prognosis in AML. The routine workup of FLT3 screening and the potential of targeting FLT3 inhibition for high-risk MDS may be taken into consideration in the future.