Baseline levels of tumor markers, including carcinoembryonic antigen (CEA), cytokeratin-19 fragment (CYFRA 21–1), neuron-specific enolase (NSE), carbohydrate antigen 19–9 (CA19-9), and carbohydrate antigen 125 (CA125), have been proven to be associated with the prognosis of patients with advanced lung cancer receiving platinum-based chemotherapy [12–14]. The gene discussed is CEACAM5; the disease is lung cancer.