pl20-catenin, a member of the Armadillo gene family, has emerged as both a master regulator of cadherin stability and an important modulator of small GTPase activities.Therefore, it plays novel roles in tumor malignant phenotype, such as invasion and metastasis.We have reported previously that abnormal expression of pl20-catenin is associated with lymph node metastasis in lung squamous cell carcinomas (SCC) and adenocarcinomas.To investigate the role and possible mechanism of pl20-catenin in lung cancer, we knocked down p120-catenin using siRNA.