BCR and chronic myelogenous leukemia, BCR-ABL1 positive: Chronic myeloid leukemia (CML) is a malignant cancer that originates from hematopoietic stem cells [99], the critical causative event in CML is the formation of the Philadelphia chromosome, a product of a chromosomal translocation that brings together the ABL gene on chromosome 9 and the BCR gene on chromosome 22.