Patterns of chromosome abnormalities in a sample of Colombian patients with chronic myeloid leukemia

Chronic Myeloid Leukemia (CML) is characterized by the presence of the Philadelphia (Ph) chromosome, resulting from a translocation between chromosomes 9 and 22 that gives rise to the BCR-ABL1 fusion gene. The Ph chromosome is present in 95 % of CML cases. In 5 %-10 % of these cases Ph variants occur and, approximately 5 % of these cases present with additional chromosomal abnormalities (ACAs). In this work we describe the prevalence of chromosome abnormalities in a sample of Colombian CML patients. A descriptive cross-sectional study was conducted, analyzing cytogenetic and molecular data from 142 CML patients. Data were collected between 2016 and 2019 at the laboratory of Biogenética Diagnóstica S.A.S. Among the 142 patients were analyzed, 56 % were male, and the average age was 45 years. The Ph chromosome was observed in 81 % of the cases. Three-way chromosome variants involving chromosomes 3, 7, and 8 were detected. The most frequent additional chromosomal aberration was +der(22)t(9;22). Atypical patterns associated with poor prognosis were found, via FISH analyses, in 88.2 % of the patients. The BCR-ABL1 fusion gene was detected in 100 % of the 18 patients subjected RT-PCR tests. This retrospective study reveals intriguing findings regarding chromosomal abnormalities in Colombian patients with CML, including rare three-way chromosome variants and atypical FISH patterns associated with a poor prognosis. Further investigation is warranted to explore the clinical implications, prognosis, and survival outcomes associated with these cytogenetic findings in CML patients.