Imatinib, an inhibitor of breakpoint cluster region protein (BCR)-ABL, platelet-derived growth factor receptor (PDGFR), and c-Kit, was the first FDA-approved small molecule tyrosine kinase inhibitor, indicated for the treatment of Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia (CML), acute lymphatic leukemia (ALL), and other types of cancer [3]. The gene discussed is PDGFRB; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.