Abstract: ObjectiveTo study the expressions and significances of leptin, estrogen and estrogen receptor (ER) in pulmonary squamous carcinoma and adenocarcinoma. MethodsThe expressions of leptin and estrogen receptor were detected in 58 cases of lung adenocarcinoma and 63 cases of pulmonary squamous cell carcinoma and 50 cases of normal lung tissue samples by immunohistochemical menthod, the levels of estrogen were also detected in patients with venous blood at the same time. Comparison of differential expression of leptin, estrogen and estrogen receptor in lung adenocarcinoma and lung squamous cell carcinoma, normal tissues, and explore their relationships with lung adenocarcinoma. ResultsLeptin, estrogen and estrogen receptor positive rates in lung adenocarcinoma group were 65.5%, 36.2% and 58.6% respectively, and 33.3%, 15.9%, 30.2% in lung squamous cell carcinoma group. There were a statistical difference between the two groups (χ2=4.324, P<0.050; χ2=5.372, P<0.050; χ2=5.718, P<0.050). In the normal control group the positive rates were 24.0%, 4.0% and 0 respectively, and there was a statistical difference compared with lung adenocarcinoma group (χ2=7.126, P<0.010; χ2=9.683, P<0.005; χ2=22.308, P<0.005). In lung adenocarcinoma group, leptin, estrogen and estrogen receptor positive rate have no relationships with tumor stage (χ2=0.001, P=0.950; χ2=0.061, P=0.900; χ2=0.178, P=0.750) and primary tumor size (χ2=0.023, P=0.900; χ2=0.001, P=0.950; χ2=0.001, P=0.950). ConclusionLeptin, estrogen and ER were expressed highly in adenocarcinoma of lung tumor. The expressions of leptin, estrogen and ER may associated with the carcinogenesis, development and clinical type of adenocarcinoma of lung.