In the current study, we screened and eventually selected 1 human bronchial epithelial cell line (HBE) and 3 lung cancer cell lines (H460, SPC and LTE), of which E-cadherin is localized to the cell membrane in 2 and cytoplasm in the other 2 cell lines, respectively, and knocked down p120ctn using small interfering RNA (siRNA). The gene discussed is CTNND1; the disease is lung carcinoma.