ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: The Philadelphia chromosome, resulting from a reciprocal translocation between chromosomes 9q34 and 22q11, generates a 190- or 210-kDa fusion protein BCR-ABL identified in more than 95% of chronic myeloid leukemia (CML) and half of patients with adult-onset acute lymphoblastic leukemia (ALL) [41, 71–73].