Distribution of BCR::ABL1 Transcripts in the Different Clinical Phases of Chronic Myeloid Leukemia: Effect on Hematological Parameters and Patient Survival.

Chronic myeloid leukemia (CML) is a hematopoietic stem cell disorder characterized by the presence of the Philadelphia chromosome, a product of the reciprocal translocation t(9;22)(q34;q11), in the BCR and ABL genes. These rearrangements in both genes lead to the formation of various fusion mRNA products, with preferential expression of , , and other mRNA variants, combined with additional chromosomal abnormalities. Notably, the distribution and frequency of different mRNA variants vary in different populations. However, studies concerning this in Mexico are limited, and the results have been inconclusive. This study therefore aimed to determine the distribution of mRNA variants in different clinical phases of CML and their effect on hematological parameters and patient survival. This study included 33 patients, whose demographic, clinical, and molecular data on mRNA variants and hematological parameters were collected to identify potential associations. A total of 84.8% (n = 28) of patients had translocation and increased platelet and basophil counts. The most frequent mRNA variant was (64.3%), followed by (28.6%) and (3.6%). Concerning the clinical phases of CML, 75.8% (n = 25), 21.2% (n = 7), and 3% (n = 1) of patients were in the chronic, blast, and accelerated phases, respectively. Moreover, the mRNA variant was more commonly identified in patients in the chronic phase. No correlation was observed between mRNA variant expression and patient survival. However, was indicative of patients with longer survival as well as those treated with imatinib or nilotinib. Additionally, platelet count could be a marker of translocation.