Several markers in peripheral blood are routinely applied for NSCLC diagnosis, including squamous cell carcinoma antigen (SCCA), neuron-specific enolase (NSE), carcinoembryonic antigen (CEA), cytokeratin 19 fragment (CYFRA21-1), and carbohydrate antigen 125 (CA125) [32, 33]. The gene discussed is CEACAM5; the disease is non-small cell lung carcinoma.