As an example, the BCR-ABL fusion gene could be detected with fluorescence in situ hybridization (FISH) in canine chronic myelogenous leukemia (CML) and chronic monocytic leukemia, which is equivalent to the Philadelphia chromosome (with the BCR-ABL fusion) in human CML showing equal genomic break sites [24,25]. The gene discussed is BCR; the disease is chronic monocytic leukemia.