BCR and chronic myelogenous leukemia, BCR-ABL1 positive: Chronic myeloid leukemia is a myeloproliferative disorder characterized by the disease-causing translocation t(9;22), which gives rise to a shortened chromosome 22, the Philadelphia chromosome (Ph) [45,46] The translocation results in a fusion between the genes encoding the ABL tyrosine kinase and BCR, giving rise to the corresponding fusion protein: BCR-ABL.