Epithelial membrane protein 3 is frequently shown as promoter methylation and functions as a tumor suppressor gene in non-small cell lung cancer

Abstract

Epithelial membrane protein 3 (EMP3) is a typical member of the epithelial membrane protein (EMP) family which has been reported to be a tumor suppressor gene in neuroblastomas and gliomas and recently reported to be commonly repressed in esophageal squamous cell carcinoma (ESCC) cell lines. However, the expression and clinical significance of EMP3 protein in lung cancer have not yet been elucidated. In this article, we detected that the expression of EMP3 in non-small cell lung cancer was significantly lower than the expression of normal lung tissues (P<0.01) by western blot. EMP3 expression in Lung cancer was significantly related to p-TNM stage (P<0.05) and EMP3 was negatively correlated with proliferation marker Ki67(r=−0.775; P<0.01), However, no significant correlations were found between EMP3 and other clinical parameters. The post-recurrent survival after radical surgery was poorer in lung cancer patients with lower EMP3 expression (P<0.01). While in vitro, following release from serum starvation of A549 NSCLC cell, the expression of EMP3 was deregulated. Thus, our finding suggests that EMP3 may be a tumor suppressor gene at the late step of lung cancer, and EMP3 may be a potential prognostic marker and therapeutic target of NSCLC.