Abstract: Objective To investigate the expression and significance of cyclin D1 in female pulmonary adenocarcinoma patients.Methods Western blot was used to detect the expression of cyclin D1 in 135 female pulmonary adenocarcinoma and normal tissue.Results Sixty cases of female pulmonary adenocarcinoma showed positive immunoreactivity for cyclin D1,and the expression level of cyclin D1 was significantly higher in tumor samples than in normal controls(P<0.05).Cyclin D1 expression was higher in patients with tumorsize more than 3cm(P<0.05),but was not associated with different tumor position,age and tumor differ entiation grade.Conclusion Cyclin D1 overex pression might be implicated in the oncogenesis of lungcancer,and could be a predictive molecular marker for poor prognosis in resectable lung cancer patients.