The implementation of precision medicine has changed treatment paradigms in several settings, including EGFR and ALK inhibitors in non-small cell lung cancer [4–6], BRAF inhibitors in malignant melanoma [7], BCR-ABL inhibitors in chronic myelogenous leukemia [8], and PARP inhibitors in breast and ovarian cancers [9–11], among several others [12]. The gene discussed is ABL1; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.