Comparison of Delta- PCR and Conventional Fragment Analysis for the Detection of FLT۳-ITD Mutations in Paired Diagnosis-Relapse Samples of Patients with Acute Myeloid Leukemia

Background & Objective: FLT۳-ITD mutation detection has been an integral part of diagnostic work ups focused on acute myeloid leukemia. However, some studies have indicated that the mutation is unstable during the 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. Materials & Methods: In this retrospective study, paired diagnosis-relapse bone marrow or peripheral blood samples from ۱۸۰ adult AML patients were analyzed for FLT۳-ITD mutations using conventional fragment analysis and Delta-PCR methods. A dilutional experiment of DNA derived from a FLT۳-ITD mutated patient in normal peripheral blood was performed in order to evaluate the sensitivity of each method. Results: All samples were analyzed using both conventional fragment analysis and Delta-PCR methods. FLT۳-ITD mutations were detected in ۲۴ diagnostic samples (۱۳.۳%) and ۲۸ relapse samples (۱۵.۵ %) through conventional fragment analysis. Three out of four patients who were FLT۳-ITD positive in the relapse samples had a mutation in the diagnostic samples using the Delta-PCR method. On the other hand, at the time of diagnosis and relapse, the mutation test results were incompatible in only ۳.۶% of patients based on the results of the Delta-PCR method compared to ۱۴.۲ based on conventional fragment analysis. Our findings revealed that the sensitivity of Delta - PCR as related to FLT۳-ITD detection was ۰.۲ %. Compared to the conventional fragment analysis, with a sensitivity of ۲%, Delta - PCR shows greater sensitivity and specificity. Conclusion: The conventional testing of the FLT۳-ITD mutation by fragment analysis did not detect a significant proportion (۱۱%) of FLT۳-ITD positive samples in AML patients. Delta PCR increased the sensitivity and specificity relative to the conventional method. The detection of FLT۳-ITD mutation through Delta PCR is important in order to detect minor clones at diagnosis or during the monitoring of AML patients.

کلیدواژه ها:

Acute myeloid leukemia ، Delta-PCR ، FMS-like tyrosine kinase ، Internal tandem duplication