Frequency of bcr1 and bcr3 PML/RARA transcripts in Sudanese Patients with Promyelocytic Leukaemia

Abstract

Background: Patients with acute promyelocytic leukemia (APL) usually express one of 3 primary hybrid transcripts of t(15;17). The 3 fusion transcripts within the promyelocytic leukemia (PML) gene are a result of heterogeneous breakpoint in the cluster regions (bcr) described as bcr1 (long), bcr2 (variant), and bcr3. Objective: This study aimed to determine the frequency of bcr transcripts in Sudanese patients with APL. Materials and methods: Peripheral blood samples were collected in EDTA blood tube for molecular and haematological investigations and bone marrow aspirates were collected for examination of promyelocytes morphology. Samples were obtained from patients referred to the Radioisotope center of Khartoum (RICK), Sudan. Genomic DNA was extracted from peripheral leucocytes and RT-PCR and nested PCR techniques were performed using primers specific for bcr1 and bcr3. Following a successful amplification of DNA by PCR, the amplified fragments were separated using agarose gel electrophoresis. Results: The heterozygous genotype Bcr1/Bcr3 was the most frequent (52.0 %) among APL patients followed by the genotype Bcr3/Bcr3 (25.3%) and Bcr1/Bcr1 (22.7%) respectively. Statistically, significant association between genotypes and each of the patients' gender or cell granulation was not was found (P>0.05). There was no statistically significant difference in haematological parameters compared to patients with different genotypes. Conclusion: The heterozygous bcr1/bcr3 genotype was the most prevalent in Sudanese patients with APL followed by the homozygous genotypes bcr3/bcr3 and bcr1/bcr1 consequently.