ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: Chronic myeloid leukemia (CML) is a clonal myeloproliferative disorder characterized by the presence of a balanced reciprocal translocation between the breakpoint cluster region (BCR) gene on chromosome 22q11.2 and the Abelson gene (ABL1) on chromosome 9q34, resulting in the formation of t(9;22)(q34;q11) (Di Bacco et al., 2000).