Introduction: Despite the impressive responses achieved with tyrosine kinase inhibitor (TKI) therapy, treatment resistance develops in 16-33% of patients of chronic myelogenous leukemia (CML). Of the BCR-ABL1 dependent mechanisms, mutations in the tyrosine kinase domain (TKD) are the commonest cause of resistance.
Material and methods: Allele specific oligonucleotide - polymerase chain reaction (ASO-PCR) was done for testing the six common TKD mutations, T315I, G250E, E255K, M244V, M351T, and Y253F.
Results and conclusion: TKD mutation study was done on 83 patients. Of these 44 (53%) were positive for one or more mutations. On analyzing specific mutations, E255K was the commonest mutation seen in 24 (29%) cases, followed by T315I in 23(28%) cases. Y253F mutation was not seen in the present study sample. In the present cohort of 83 patients, 29 (35%) cases were positive for single mutation, 12 (14%) had two mutations and 3 (4%) had three mutations.
Keywords: ASO-PCR; imatinib resistance; tyrosine kinase domain mutations.