To test our hypothesis in the present study, we reconstituted p120ctn-1A and 3A respectively in p120ctn depleted cells and overexpressed or knocked down Kaiso or β-catenin to test the effects on expression of cyclin D1 and cyclin E. The objective was to investigate the potential different molecular mechanisms by which p120ctn-1 and 3 regulate cell proliferation and the cell cycle in lung cancer cells. The gene discussed is CCND1; the disease is lung carcinoma.