Sensitive allele specific oligonucleotide-polymerase chain reaction in detection of preexisting mutations in imatinib-resistant chronic myelogenous leukemia patients: A retrospective analysis

Introduction: Pre-existing BCR-ABL kinase domain mutation leads to Imatinib resistance. Methods: Retrospective analysis of 50 patients of Imatinib resistance was done in GCRI, from January 2014 till May 2014. Allelle Specific Oligonucleotide–Polymerase Chain Reaction (ASO-PCR) was performed on Genomic DNA, of peripheral blood mononuclear cells (PBMCs). Results: 47 (94%) were in Chronic phase, 2 (4%) in accelerated phase, 1 (2%) in blastic crisis. Median duration of Imatinib was 48 months. 43/50 had one or more than 1 mutation, T315I mutation in 5 (10%) patients, M351T in 32% (16/50) and F311L in 8. Conclusion: We report low cytogenetic response (25%) and durability of response to 600 mg of Imatinib, even in M351T mutation.