B-239 Characterization and Frequency of Cytogenetic Findings in Patients with Chronic Myeloid Leukemia

Abstract Background Chronic Myeloid Leukemia (CML) is a myeloproliferative disorder that accounts for 15% to 20% of leukemias. It is characterized by the expansion of hematopoietic progenitor cells, leukocytosis with left shift, splenomegaly and the presence of the Philadelphia chromosome (Ph), resulting from a translocation between chromosomes 9q34 and 22q11, which generates the BCR-ABL gene. This gene leads to the production of the BCR-ABL protein, which stimulates cell proliferation and inhibits apoptosis, reinforcing the importance of this molecular alteration in the study and treatment of the disease. The Ph chromosome is identified in the chronic phase of CML. As the disease progresses, other chromosomal alterations may appear. The aim of this study was to evaluate the main cytogenetic findings in patients diagnosed or under investigation for CML, with a focus on identifying the most frequent chromosomal alterations. Methods A total of 237 karyotypes were analyzed from patients aged between 8 and 90 years, with suspected or confirmed CML, between July 2021 and October 2024. Results Of the 237 samples analyzed, 53.6% came from male patients and the most prevalent age group in males was 51 to 60 years (26.2%), while in females the 41 to 50 age group was predominated (28.5%). Among the patients evaluated, 36.7% (87/237) had normal karyotype results. Of these, 43.8% (38/87) were under investigation for CML, but the hypothesis was ruled out, 5.7% were not diagnosed due to a lack of clinical information and complementary tests, and 50.5% of the patients were undergoing treatment, which may have influenced the normal karyotype. Among the patients undergoing treatment, the most prevalent age group was 61 to 70 years, representing 34.1% of the cases. In addition, 3.45% of the patients were aged between 11 and 18. The presence of Philadelphia chromosome was detected in 58.2% (138/237) of patients. The most affected age group was 51 to 60 years, corresponding to 22.5% of cases, while 5.8% were aged between 11 and 17. The variant Philadelphia chromosome was identified in 2.95% (7/237) of patients. The other chromosomes detected were 3, 6, 9, 12, 14, 17 and 21, with the translocation involving chromosome 9 occurring in two cases. The other translocations were identified only once. The most prevalent age was 41 to 50 years, representing 42.85% of the cases. Other five chromosomal alterations were detected, such as: (i) Trisomy of chromosome 8: detected in 0.8% (2/237) of patients, one of whom also had Philadelphia chromosome; (ii) Monosomy of chromosome 7 was identified in 0.4% of patients; (iii) Intra-chromosomal translocation on chromosome 3 was observed in 0.4% of patients, involving two regions of chromosome 3; (iv) reciprocal translocation between chromosomes 5 and 15 was present in 0.42% of the patients. Conclusion The Philadelphia chromosome is a robust biomarker for CML, standing out in the diagnosis and monitoring of the disease. The use of cytogenetic techniques is essential for identifying chromosomal alterations, allowing for identification and a personalized therapeutic approach, optimizing the effectiveness of the clinical management of these patients.