Pattern of PML/RARα BCR Isoforms in Acute Promyelocytic Leukemia (APL) Patients in Bangladesh - A Single Centre Study

Abstract

Background: Acute Promyelocytic Leukemia (APL) is a well-defined subtype of AML accounting for 5-13% of all AML cases and is identified by a balanced reciprocal translocation between chromosome 15 and 17 [t(15;17)(q24;q21)] which ultimately causes formation of PML-RAR_ oncoprotein. This translocation results in 3 isoforms on the PML gene including L-long form (located at intron 3) termed bcr1, S-short form (located at intron 6) known as bcr2, and V form (located at exon 6) known as bcr3. To ascertain the pattern of different breakpoints of PML/RAR_ fusion gene among Bangladeshi APL patients was the aim of this study. Methods: In this study 60 APL patients diagnosed positive for PML-RAR_ fusion gene who were referred to AFIP, Dhaka Cantonment were included as subjects. They were analyzed for the detection of three possible PML-RAR_ isoforms by utilizing Real Time Polymerase Chain Reaction (RT-PCR) technology. Results: The patients included in this study have age ranged from 9 years to 72 years, 35 years is the mean of age. In the study group, 39 (65%) were male and female patients were 21 (35%). The bcr1 isoform was found in 4 (6.67%) patients. No single bcr2 isoform was found in any patient. But in 3 patients having bcr2 isoform were found along with bcr1 (5.0%) and in 1 (1.66%) patient it was present in addition to bcr3. The bcr3 isoform was found in 19 (31.67%) patients and in 33 (55.0%) patients all of the isoforms were present. Conclusion: The key elements for the proper management of APL include early diagnosis and treatment initiation, proper supportive care, and recognition and management of therapy associated complications. Genetic testing is one of the most accurate methods for the diagnosis of this disease and ultimately can help in advancement of the disease management.

Bangladesh Armed Forces Med J Vol 58 No (1) June 2025, pp 55-60