ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: CML is characterized by recurrent genetic aberration in leukemic stem cells, namely the Philadelphia chromosome caused by reciprocal translocation t(9;22)(q34;q11) that leads to the formation of BCR::ABL1 fusion oncogene (Nowell and Hungerford 1960; Rowley 1973).