BCR and chronic myelogenous leukemia, BCR-ABL1 positive: Chronic myelogenous leukemia (CML) is the most common myeloproliferative disease, and the majority of cases of CML have a (9;22) cytogenetic disorder, resulting in Breakpoint Cluster Region/ Abelson murine leukaemia (BCR/ABL) fusion which activates tyrosine kinase and leads to the uncontrolled proliferation of myeloid cells (1–3).