ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: Chronic myeloid leukaemia is a clonal myeloproliferative disorder that originates from a pluripotent stem cell expressing the Ph chromosome (t(9;22) chromosomal translocation) with the constitutively active BCR-ABL fusion gene, which leads to the production of the p210 BCR-ABL protein [40].