BCR and chronic myelogenous leukemia, BCR-ABL1 positive: Chronic myelogenous leukemia (CML) is a malignant hematopoietic stem cell disease, produced through the balance translocation between the long arms of chromosomes 9 and 22, so-called the Philadelphia chromosome.[1] It is a result of a combination of two genes Breakpoint cluster Region (BCR) and Ableson (ABL) that form the fusion gene BCR–ABL that produces a chimeric protein, tyrosine kinase activity.