Frequency of BCR-ABL fusion transcripts in Serbian patients with chronic myeloid leukemia

Abstract

Purpose: The aim of this study was to analyze the occurrence of the most frequent BCR-ABL transcript variants (b3a2, b2a2 and ela2) in Serbian patients with chronic myeloid leukemia (CML) and compare it with the occurrence reported in other populations. Methods: We analyzed peripheral blood and bone marrow samples of 136 Serbian patients with CML by RT-PCR and cytogenetic methods. Results: In 100 patients (73.5%) the b3a2 and in 34 (25%) the b2a2 forms of BCR-ABL were detected. One (0.75%) patient was BCR-ABL negative, but in lymphoblastic transformation he expressed the ela1 transcript of BCR-ABL. One (0.75%) patient displayed both b2a2 and b3a2 forms of BCR-ABL. Analysis of this group according to karyotype showed b3a2 predominance (79%) in patients with classic t(9;22); b2a2 was found in 20% and both b2a2 and b3a2 forms in 1%. In variant translocations b3a2 in 65% and b2a2 in 35% of the patients were detected. In contrast, the subgroup with normal karyotype expressed slight predominance of the b2a2 form (50%); b3a2 was found in 43% of the patients and one patient (7%) displayed ela2. Conclusion: Predominance of the b3a2 form in Serbian patients with CML is in concordance with other relevant investigations, conducted mostly on Caucasian ethnic groups, but in contrast to the study performed on the Mestizo ethnic group in Ecuador Slight predominance of the b2a2 form was also noticed among the patients with normal karyotype.