Frequency of occurrence of BCR-ABL transcripts in patients with ХМЛ in Kazakhstan

Abstract

Relevance. The chimeric BCR-ABL gene caused by the t(9;22)(q34;q11.2) translocation results in the formation of transcripts (b2a2, b3a2, e1a2, e19a2), which play a key role in diagnostics, determination of sensitivity to therapy, and prognosis of chronic myeloid leukemia (CML). Purpose of the study. To determine the frequency of BCR-ABL transcripts in patients with CML in the population of the Republic of Kazakhstan. Materials and methods. The study material was the peripheral blood of patients admitted from various regions of the Republic of Kazakhstan, who had t(9;22)(q34;q11.2 at debut. RNA was isolated using the GeneJET kit. BCR-ABL transcripts were detected using the High Capacity cDNA Reverse Transcription Kit (ThermoFisher). RT-PCR was performed on a QuantStudio 12 Flex analyzer (Applied Biosystems). The ABL gene served as a control. The average age of patients was 45±5 years. Results and discussion. In total, 839 studies were conducted in 554 patients from 2018 to 2025, of which 57 patients underwent follow-up examinations every 6 months. Women predominated in the study cohort - 53%, men accounted for 47%. The frequency of transcripts was distributed as follows: b2a2 - 70%; b3a2 - 17%; e1a2 - 12%; e19a2 - 1.0%. Co-expression of transcripts was detected during the study. The following combinations of transcripts were most common: b3a2/b2a2 - 53%; b2a2/e1a2 - 29%; b3a2/b2a2/e1a2 – 16%; b2a2/e19a2 – 1.0%; b3a2/ b2a2 /e19a2 – 1.0%. Conclusion. The most common transcript type in patients with CML in the population of the Republic of Kazakhstan is b2a2, in 51% of patients co-expression of several transcripts was detected, and the most frequently diagnosed combination was b3a2/b2a2 (53%).

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