ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: Chronic myeloid leukemia (CML) is a clonal hematopoietic stem cell disease that is characterized by the Philadelphia chromosome (Ph), which is generated by the reciprocal translocation t(9;22)(q34;q11) that results in the fusion of the c-abl oncogene 1 (ABL1) with the breakpoint cluster region (BCR) gene[1].