BCR and chronic myelogenous leukemia, BCR-ABL1 positive: CML is a malignant myeloproliferative tumor characterized by the presence of the Philadelphia chromosome caused by the reciprocal translocation t (9, 22) (q34; q11) between breakpoint cluster region (Bcr) and Abelson murine leukemia (Abl) genes, resulting in the formation of the Bcr-Abl fusion gene.