ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: The hematopoietic neoplasm chronic myelogenous leukemia (CML) is a rare disorder predominantly caused by reciprocal translocation t (9; 22) (q34; q11) resulting in formation of the so-called Philadelphia chromosome (Ph) and the BCR-ABL1 fusion gene (Nowell and Hungerford, 1960; Rowley, 1973; Heisterkamp et al., 1983).