ALK and cancer: Since US Food and Drug Administration (FDA) approved imatinib for the treatment of chronic myeloid leukemia in 2001, multiple potent and well-tolerated TKIs—targets including EGFR, ALK, ROS1, HER2, NTRK, VEGFR, RET, MET, MEK, FGFR, PDGFR, and KIT—have been emerging and contributing to the significant progress in cancer treatment.