Molecular Epidemiology of BCR-ABL Rearrangement Variants in Chronic Myeloid Leukemia and Acute Lymphocytic Leukemia from Major Institute of Pakista

Abstract

In Pakistan the disease burden of Chronic Myeloid Leukemia (CML) and Acute Lymphoblastic Leukemia (ALL) is quite high, yet there is a lack of scientific evidence regarding the spectrum of BCR-ABL rearrangement variants in CML and ALL. Knowing about BCR-ABL rearrangement is important in determining the prognosis and treatment strategy of disease at the time of diagnosis. This study included a total of 685 patients, out of which there were 644 CML patients and 41 ALL patients, from October 2016-July 2019. From the CML group, 270 patients were reported to have the BCR-ABL1 transcript, from which 50% were males. Whereas in the ALL group, 35 patients were reported to have the BCR-ABL1 transcript out of which 65.7% were males. Proportions of BCR-ABL transcript type differed between the two groups, with b3a2 (63.3%) and b2a2 (34.8%) transcript types having the highest frequency in CML patients, whereas e1a2 (77.1%) and b3a2 (11.3%) transcript types were found to have the highest frequency in ALL patients. Our data shows transcript genotypes in CML and ALL patients in an Asian population, which may be useful to guide the clinical management and assess prognosis. Since the majority of our CML population had the b3a2 transcript, they have a better prognosis and treatment response.