In this study, we used immunohistochemistry to systemically analyze the expression of SOX2 in various types of lung cancers and found that SOX2 is predominantly overexpressed in adenocarcinoma, SCC, large cell carcinomas and SCLC tissues, indicating that SOX2 can be used as a universal marker for the diagnosis of human lung cancer. The gene discussed is SOX2; the disease is small cell lung carcinoma.