ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: Chronic myelogenous leukemia (CML) is a myeloproliferative neoplasia caused by the translocation t(9;22)(q34;q11) in the pluripotent hematopoietic stem cell with formation of a constitutively active BCR-ABL1 tyrosine kinase.1