A high level of TM4SF5 is associated with human esophageal cancer progression and poor patient survival.

PURPOSE: We investigated expression of TM4SF5 and its involvement in human esophageal cancer (HEC).
METHODS: We analyzed TM4SF5 expression in normal esophageal epithelial cells (HEEC), in four HEC cell lines, and in 20 HEC clinical tissue samples and matched nontumor samples. The effect of TM4SF5 on HEC cell proliferation and metastasis and invasion was assessed, and the relationship between TM4SF5 and integrin β1 was determined. Finally, TM4SF5 and integrin β1 expression were further examined by use of immunohistochemistry (IHC) and tissue microarray analysis, and the prognostic use of TM4SF5 and integrin β1 in HEC was evaluated.
RESULTS: TM4SF5 was more highly expressed in HEC cells and in HEC tissues than in HEEC and matched nontumor tissues. Down-regulation of TM4SF5 in KYSE150 cells reduced cell proliferation and metastasis and invasion whereas metastasis and invasion by KYSE510 increased after TM4SF5 cDNA transfection. In HEC cells, TM4SF5 formed a complex with integrin β1, and interference with integrin β1 in KYSE510-TM4SF5 cells markedly inhibited cell invasion on laminin 5. Our findings also showed that TM4SF5 and integrin β1 overexpression correlated with low differentiation and high stage (p<0.05, respectively). Postoperative 5-year overall survival of patients with TM4SF5low and/or integrin β1low was higher than for patients with TM4SF5high and/or integrin β1high. Multivariate analysis demonstrated that TM4SF5 and integrin β1 co-overexpression was an independent prognostic marker for HEC.
CONCLUSION: TM4SF5 is positively associated with HEC invasiveness. The combination of TM4SF5 with integrin β1 could potentially serve as a novel marker for predicting HEC prognosis.