CEACAM5 and lung cancer: Neurocyte-specific enolase (NSE), carcinoembryonic antigen (CEA), cytokeratin fragment (CYFRA21-1), pro-gastrin-releasing peptide (pro-GRP), and carbohydrate antigen 125 (CA125) are routine markers recommended by the National Academy of Clinical Biochemistry (NACB) guidelines for laboratory medicine in lung cancer.