BCR and acute lymphoblastic leukemia: Taken together, we show for the first time that t(9;22) gives rise to two fusion proteins with leukemogenic potential, BCR/ABL and ABL/BCR, and our data provide the first evidence that, in m-BCR-positive ALL, p96ABL/BCR cooperates with p185BCR/ABL in the determination of the leukemic phenotype.