BCR-ABL1 Transcript Variants in Chronic Myeloid Leukemia Patients in Africa: A Systematic Review

The BCR-ABL1 fusion gene is present in more than 95% of cases of chronic myeloid leukemia (CML), the disease in which it was first described. There are different BCR-ABL1 fusion transcripts depending on the location of the breakpoints during chromosomal translocation. Identifying these transcripts is important for treatment monitoring. The objective was to determine the frequency and distribution of BCR-ABL1 transcripts in African countries.

The articles were sourced from scientific databases such as PubMed, Google Scholar, and the BioMed Central databases. The systematic review was conducted in accordance with the PRISMA guidelines. Data extraction was performed using Excel 2016.

Eight original articles, representing seven African countries and involving a total of 1258 patients with CML, were selected based on the established criteria. The mean age of patients at diagnosis was 40.55 years, ranging from 9 to 87 years. The two main transcripts were e14a2 and e13a2. In most African studies, e14a2 was more prevalent than e13a2 (51.35% vs. 38.55%). The Nigerian population showed a relatively high frequency of co-expression of e14a2 and e13a2. The other transcripts identified were e19a2, e1a2, e13a3, and e6a2, accounting for 1.74% of the total number of identified transcripts. Age and sex did not appear to have an effect on transcript types in most countries, with the exception of Sudan and Tunisia. Certain associations were observed between BCR-ABL variants and hematological parameters, particularly white blood cell and platelet counts.

There are few studies in Africa on the frequency of BCR-ABL1 gene variants. The main transcripts identified were e14a2 and e13a2. In most cases, the e14a2 variant is more common than the e13a2 variant. Some studies have reported an association with white blood cell and platelet counts in the complete blood count. There is a significant gap in molecular diagnostics in Africa.