ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: Chronic myeloid leukemia (CML) is a clonal myeloproliferative neoplasm characterized by the presence of the Philadelphia (Ph) chromosome derived from a reciprocal translocation between chromosome 9 and 22 (t(9;22)(q34;q11) to produce BCR::ABL1 oncogene [1, 2].