CEACAM5 and non-small cell lung carcinoma: This report presents an elderly patient with non-small cell lung cancer (NSCLC) and a Y1003S mutation in MET detected by next-generation sequencing (NGS).<h4>Case report</h4>In October 2020, a 91-year-old male was admitted to the Department of Respiratory and Critical Care Medicine, Ruijin Hospital because of an increased carcinoembryonic antigen.