Translocation between chromosomes 9 and 22 causes the production of the oncogenic fusion protein BCR-ABL1, constitutively active and responsible mainly for the development of chronic myeloid leukemia (CML) and a small proportion of B progenitor acute lymphoblastic leukemia (B-ALLs). Here, BCR is linked to chronic myelogenous leukemia, BCR-ABL1 positive.