The expressions of Claudin-7 and Slug in proteins were detected in 101 cases of lung squamous cell carcinoma and adenocarcinoma samples by immunohistochemistry SP method, and Western blot was applied to detect the expressions of Claudin-7 and Slug in 30 specimens of fresh lung cancer and corresponding paracancerous tissues. The gene discussed is CLDN7; the disease is adenocarcinoma.