The driver mutation to cause CML results from a reciprocal translocation between chromosomes 9 and 22 [(t(9;22) (q34;q11.2)], combining the abelson murine leukemia (ABL) proto-oncogene on chromosome 9 with the breakpoint cluster region protein (BCR) sequences on chromosome 22 to form the BCR-ABL fusion gene [88,89]. The gene discussed is BCR; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.