CEACAM5 and non-small cell lung carcinoma: For example, carcinoembryonic antigen (CEA), squamous cell carcinoma antigen (SCC-Ag), carbohydrate antigen 125 (CA125) and cytokeratin fragment 21–1 (CYFRA21-1) have been widely used as serum biomarkers for early diagnosis and assessment of NSCLC [13].