CEACAM5 and neoplasm: Currently, some serum tumor markers, such as carcinoembryonic antigen (CEA), squamous cell carcinoma antigen (SCCA) and cytokeratin 19 fragment (CYFRA21‐1), are being employed extensively to diagnose NSCLC due to the rapid detection methods available (Chen et al., 2015; Zhao et al., 2015b).