Over the past 10 years, great advances in molecular biology have enabled the discovery of various driver mutations of lung adenocarcinomas, including the epidermal growth factor receptor (EGFR), ALK, AKT1, BRAF, HER2, KRAS, MET, PIK3CA, RET, ROS1. The proliferation of tumor cells that originates from a single oncogene mutation is termed as an ‘oncogene addiction’. The gene discussed is RET; the disease is neoplasm.