Expression Analysis of Aquaporin-1 (Aqp-1) in Human Biliary Tract Carcinoma

Abstract

Background: Aquaporins (AQPs) are important in controlling bile water secretion. AQP is related to the invasion and metastasis of cancer. However, the relationship of biliary tract cancer is not clear. The role of AQP-1 in cancer cell is also unknown. Methhods: We analyzed AQP-1 expression using tissue microarray (TMA) in 99 samples immunohistochemically (50 gallbladder carcinoma, 39 bile duct carcinoma and 10 Papilla Vater carcinoma patients who underwent surgery at our department from 1997 to 2011). Gene expressions were evaluated by the combination of the immunohistological intensity and distribution. The expression level is compared to the clinico-pathological data of the patients. Results: In the TMA, depth of tumor invasion and histological type are associated with AQP-1 expression. The group of patients with high AQP-1 expression is associated with higher rates of disease specific survival (log-rank p = 0.013). Cox’s proportional hazard model reveals that AQP-1 expression is an independent prognostic factor (RR, 0.324; p = 0.001) in multivariate analysis. There is a correlation between AQP-1 expression and tumor invasion. Conclusions: These observations of this study suggest that AQP-1 expression may be favorable biomarkers associated with prognosis and tumor invasion in biliary tract carcinoma.