3 ISOFORMS OF PML RARα IN ACUTE PROMYELOCYTIC LEUKAEMIA.

Objective: To determine the frequencies of three isoforms of PML RARα fusion gene in APL. Study Design: Descriptive cross sectional study. Place and Duration of Study: Department of Hematology, Armed Forces Institute of Pathology (AFIP), Rawalpindi Pakistan, from Apr 2015 to Oct 2015. Material and Methods: This study involved 97 newly diagnosed cases of APL, aged between 15-70 years from both genders. Double nested PCR was carried out by Applied Biosystems 2720 Thermal Cycler in every patient to determine the isoform of PML RARα fusion gene. A written informed consent was obtained from every patient. Results: The age of the patients ranged from 17 years to 69 years with a mean of 37.87 ± 12.89 years. There were 68 (70.1%) male and 29 (29.9%) female patients in the study group. The bcr1 isoform was found in 9 (9.3%) patients. There was no significant difference in the frequency of bcr1 isoform across age groups; 17-34 years vs. 35-52 years vs. 53-69 years (14.6% vs. 7.0% vs. 0.0%; p=0.223) and genders; male vs. female (7.4% vs. 13.8%; p=0.317). The bcr2 isoform was found in 26 (26.8%) patients. There was no significant difference in the frequency of bcr2 isoform across age groups; 17-34 years vs. 35-52 years vs. 53-69 years (19.5% vs. 27.9% vs. 46.2%; p=0.164) and genders; male vs. female (25.0% vs. 31.0%; p=0.539) while the bcr3 isoform was found in 62 (63.9%) patients. There was no significant difference in the frequency of bcr3 isoform across age groups; 17-34 years vs. 35-52 years vs. 53-69 years (65.9% vs. 65.1% vs. 53.8%; p=0.717) and genders; male vs. female (67.6% vs. 55.2%; p=0.242). Conclusion: The most frequent isoform of PML-RARα fusion gene was bcr3 which was observed in 62 (63.9%) cases followed by bcr2 (26.8%) and bcr1 (9.3%). There was no significant difference in the frequency of isoforms with patient's age and gender. [ABSTRACT FROM AUTHOR]