CEACAM5 and lung carcinoma: We report the establishment of a reference interval for six individual lung cancer biomarkers, namely the progastrin‐releasing peptide (ProGRP), neuron‐specific enolase (NSE), squamous carcinoma antigen (SCC), carcinoembryonic antigen (CEA), cytokeratin‐19 fragment (CYFRA21‐1), and human epididymis protein 4 (HE4) as phase I of our recent multi‐center clinical study series with age‐stratified, gender‐specific, large cohort, and geographic population considerations from 9 large tier‐3 hospitals in China.