Detection of FLT3 mutations in patients from eastern Slovakia

Abstract

Background: The study investigated FLT3 gene mutations in patients from eastern Slovakia using a simple molecular method. Patients and Methods: We analyzed 141 patients with primary acute myeloid leukemia (AML) and 8 patients with AML that developed from myelodysplastic syndrome (MDS) who were aged 19-81 years. DNA isolated from peripheral blood and/or bone marrow was analyzed by PCR. FLT3 internal tandem duplication (FLT3-ITD) was detected by amplification of exons 14 and 15. Point mutations in the FLT3 tyrosine kinase domain (FLT3--TKD) were detected by digesting the PCR product of exon 20 with the restriction endonuclease EcoRV. Fragments were separated electro-phoretically. PCR products of the positive samples were also analyzed using a microchip device (Bioanalyzer 2100). Results: FLT3-ITD and point mutations in the FLT-TKD were detected in 19 and 8% of patients, resp. Two patients (1%) harbored both types of mutations. Patients with and without FLT3 mutations were called FLT+ and FLT-, resp. Most FLT3+ patients had no chromosomal aberrations (59%) or harbored the t(15; 17) translocation in PML-RARA (15%). The mortality rate was 33% among FLT3+ patients and 10% among FLT3- patients. Among FLT3+ patients, the mortality rates of patients with FLT3-ITD and point mutations of the FLT-TKD were almost the same. A 77-year-old female patient with both FLT3-ITD and a point mutation in the FLT3-TKD was in remission. The eight patients who developed AML from MDS were assessed separately. Of these, three patients were FLT3+; two patients displayed FLT3-ITD, and one patient harbored a point mutation in the FLT3-TKD. No other genetic aberrations were detected. FLT3+ patients lived for longer than FLT3- patients. These analyses of FLT3 gene mutations in patients from eastern Slovakia are consistent with published data from other databases. Conclusion: The applied PCR method is reliable, relatively fast, and affordable, and can be used for routine monitoring of FLT3 gene mutations. FLT3 mutations can be verified using a microchip as an alternative to capillary electrophoresis.