Targeted therapies are often chosen for their ability to selectively target cancer cells harboring a characteristic biomarker and in certain cases have revolutionized patient care (e.g., clinical introduction of imatinib, a BCR-ABL tyrosine kinase inhibitor, has more than tripled the 5-year survival rate for patients with chronic myelogenous leukemia) (7). This evidence concerns the gene ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive.