Throughout the past 20 years, various effective small molecule TKIs have been developed for lung cancer treatment, including EGFR/ALK/ROS-1/MET/VEGFR/Human epidermal growth factor receptor 2 (HER2)/Kirsten rat sarcoma viral oncogene (KRAS)/RET proto-oncogene (RET)/neurotrophin receptor kinase (NTRK)/v-raf murine sarcoma viral oncogene homolog B1 (BRAF)/mitogen-activated protein kinase (MEK)/fibroblast growth factor receptor (FGFR)-TKIs. This evidence concerns the gene RET and lung cancer.