CEACAM5 and small cell lung carcinoma: The combination of SCCA, NSE, and CEA with the highest sensitivity (67.65%) and higher specificity (89.29%) can help in the diagnosis of AC; SCCA, CEA, and CYFRA21-1 (91.07% and 89.29%) can aid to the diagnosis of SCC; and SCCA, NSE, and CYFRA21-1 (75.00% and 88.57%) can assist in the diagnosis of SCLC.