Different Prognostic Implications of Aquaporin-1 and Aquaporin-5 Expression among Different Histological Types of Ovarian Carcinoma.

The aquaporins (AQPs) are a family of transmembrane water channel proteins that are distributed in various human tissues. Recent studies have suggested that AQP expression correlates with various aspects of cancer biology that determine the aggressiveness of different cancers. Ovarian carcinoma is one of the most lethal gynecological cancers. Some studies have suggested that AQPs are expressed in ovarian carcinoma, and are associated with cancer cell growth and migration. In this study, we immunohistochemically evaluated the expression of AQP1, 3, 5, and 9 in a total of 300 ovarian carcinomas using tissue microarrays. In our analyses of correlations between aquaporin expression and overall survival, high AQP5 expression was significantly associated with poorer prognosis (P = 0.029). For AQP1, the low expression group trended towards poorer prognosis than the high expression group, but the difference was not statistically significant. When ovarian carcinomas were divided by histological types, high AQP5 expression correlated with poorer prognosis in serous carcinoma (P = 0.015), and low AQP1 expression correlated with poorer prognosis in clear cell carcinomas (P = 0.0055). By contrast, high AQP1 expression correlated with poorer prognosis in mucinous carcinoma (P = 0.0001) and endometrioid carcinoma (P = 0.021). Our studies suggest that AQPs can be useful prognostic markers in ovarian carcinoma, but their correlation with prognosis depends on the histological type of ovarian carcinoma.