BMI1 is upregulated in patients with advanced stages of BCR-ABL-induced chronic myelogenous leukemia (CML)8 and through its repressive activity on the Cdkn2a locus18 and other less well-characterized Cdkn2a independent activities results in leukemic transformation19. This evidence concerns the gene ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive.