SOX2 and small cell lung carcinoma: To determine whether SOX2 contributes to tumorigenesis of lung cancer, an immunohistochemical method was used to detect expression of SOX2 in human lung tissues of normal/paracarcinoma (n = 38), adenocarcinoma (n = 200), SCC (n = 150), SCLC (n = 36) and large cell lung cancer (n = 31).