Predictive criteria for response to these multiple kinase inhibitors (MTKI) are not as well determined as for tumors harboring key driver alterations, such as BCR-ABL translocations in chronic myeloid leukemia (CML), KIT-mutant GIST, BRAF-mutant melanoma, and ALK-positive non-small cell lung cancer among others [5, 9, 12–17]. The gene discussed is BCR; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.