Notably, subclass-related oncogene addiction loops have been identified based on genomic profiling of various tumor subtypes.12, 13, 14, 15, 16, 17, 18 This approach has been successfully applied to the management of chronic myeloid leukemia (CML) and breast cancer.19, 20, 21 For example, most of CMLs are driven by a fused BCR-ABL oncoprotein, a constitutively activated tyrosine kinase. The gene discussed is BCR; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.