A prime example is the BCR-ABL fusion product, which results from the reciprocal t(9;22)(q34;q22) chromosomal translocation (Philadelphia [Ph1] chromosome), essential for development and sustained growth of chronic myelogenous leukemia and Ph1-positive (Ph1+) acute lymphoblastic leukemias [32]. This evidence concerns the gene BCR and chronic myelogenous leukemia, BCR-ABL1 positive.