Evaluation of FLT3-ITD mutations in paired diagnosis-relapse samples of patients with acute myeloid leukemia by Delta- PCR technique

Introduction: FLT3-ITD mutation detection has been an integral part of diagnostic workup for acute myeloid leukemia. However, some studies have indicated that the mutation is unstable during various stages of the disease. The purpose of this study was to evaluate the stability of this marker in paired diagnosis-relapse samples using Delta-PCR method.Material and methods: In this retrospective study, Paired diagnosis-relapse bone marrow/or peripheral samples from 180 adult AML patients were analyzed for FLT3-ITD mutations using conventional fragment analysis and Delta-PCR methods. A Dilutional experiment of DNA derived from a FLT3-ITD mutated patient in normal peripheral blood was performed to evaluate the sensitivity of each method.Result: FLT3-ITD mutations were detected in 24 diagnostic samples (13.3%) and 28 relapse samples (15.5%) by conventional fragment analysis. At relapse, three negative FLT3-ITD patients demonstrated FLT3-ITD mutation. The presence of the FLT3-ITD mutations in diagnostic samples was confirmed in all the three samples by Delta-PCR method. Our findings revealed the sensitivity of Delta - PCR to FLT3-ITD detection was 0.2 %. Compared to the conventional fragment analysis, with a sensitivity of 2%, Delta - PCR has shown greater sensitivity and specificity.Discussion: Conventional testing of FLT3-ITD mutation by fragment analysis did not detect a significant proportion(11%) of FLT3-ITD positive samples in AML patients. Delta PCR increased the sensitivity and specificity relative to conventional method. Detection of FLT3-ITD mutation by Delta PCR is important to detect minor clone at diagnosis or during monitoring of AML patients

Evaluation of FLT3-ITD mutations in paired diagnosis-relapse samples of patients with acute myeloid leukemia by Delta- PCR technique Keywords:

Acute myeloid leukemia , Delta-PCR , FMS-like tyrosine kinase , internal tandem duplication