Prevalence of BCR-ABL T315I Mutation in Malaysian Patients with Imatinib-Resistant Chronic Myeloid Leukemia.

Objective: Chronic Myeloid Leukemia (CML) is caused by a reciprocal translocation between chromosomes 9 and 22, t(9;22) (q34;q11) which encodes for the BCR-ABL fusion protein. Discovery of Imatinib Mesylate (IM) as first line therapy has brought tremendous improvement in the management of CML. However, emergence of point mutations within the BCR-ABL gene particularly T315I mutation, affects a common BCR-ABL kinase contact residue which impairs drug binding thus contribute to treatment resistance. This study aims to investigate the BCR-ABL T315I mutation in Malaysian patients with CML. Methods: A total of 285 patients diagnosed with CML were included in this study. Mutation detection was performed using qualitative real-time PCR (qPCR). Results: Fifteen out of 285 samples (5.26%) were positive for T315I mutations after amplification with real-time PCR assay. From the total number of positive samples, six patients were in accelerated phase (AP), four in chronic phase (CP) and five in blast crisis (BC). Conclusion: Mutation testing is recommended for choosing various tyrosine kinase inhibitors (TKIs) to optimize outcomes for both cases of treatment failure or suboptimal response to imatinib. Therefore, detection of T315I mutation in CML patients are clinically useful in the selection of appropriate treatment strategies to prevent disease progression.