CML is a clonal myeloproliferative disorder of pluripotent hematopoietic stem cells, in which a reciprocal translocation occurs between chromosomes 9 and 22, t(9;22)(q34;q11.2), resulting in the Philadelphia (Ph) chromosome, which is responsible for the expression of an abnormal fusion protein with altered tyrosine kinase activity called BCR::ABL1 [1]. The gene discussed is BCR; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.