Abstract: Objective To investigate expression and role of follistation(FS) in human lung adenocarcinoma cells.Methods FS expression in lung adenocarcinoma cells was detected with immunocytochemical staining; cell proliferation was assayed with cell counting-hit-8 and cell apoptosis was examined with flow cytometry.Results Immunocytochemical staining showed that FS was expressed in lung adenocarcinoma cells.Cell proliferation assay revealed that in 40 ng/ml and 50 ng/ml activin A groups,the proliferation of lung adenocarcinoma cells was 0.49±0.07 and 0.42±0.08,which were lower than that in control group(0.62±0.09).The results indicated that after the usage of anti-FS monoclonal antibody to neutralize endogenous FS,10 ng/ml activin A could inhibit the proliferation of lung adenocarcinoma cells(0.48±0.06),and the induced cells apoptosis(24.8±6.7) was higher than that in alone activin A group(7.3±2.4).Conclusion The results demonstrate that the expressed FS is beneficial to survival of lung adenocarcinoma cells and the blockade of FS expression and action may provide effective ways for treatment of lung adenocarcinoma.