In the present study, we demonstrated that up-regulation of BAD significantly reduced cell proliferation in H1299, H292 and SPC-A1 cell lines in vitro and H1299/SPC-A1 cell tumor growth in vivo, but has no appreciable effects on cell cycle distribution and invasion (data not shown, all p > 0.05) in all cell lines. The gene discussed is BAD; the disease is neoplasm.