Overexpression of Aquaporin-1 is a Prognostic Factor for Biochemical Recurrence in Prostate Adenocarcinoma

Aquaporins (AQP) are transmembrane proteins that provide channels for water and solutes, and some are involved in tumor progression and invasion. We evaluated the expression of AQP-1, AQP-3, and AQP-5 and their clinicopathological significance in prostate adenocarcinomas (PCA). Prostatectomy specimens (n = 99) were retrieved from the surgical pathology archives and clinicopathological data were obtained from the medical database at Kyungpook National University Hospital. Immunohistochemical staining for AQP-1, AQP-3, and AQP-5 was performed on tissue microarrays comprising paired malignant and benign prostatic tissues. Seventeen PCA cases (17.2 %) showed AQP-1 overexpression, specifically 7 tumors (9.7 %) with lower Gleason scores (GS) and 10 tumors (37.0 %) with higher GS, with statistical significance (P = 0.001). AQP-1 overexpression was significantly associated with higher GS (P = 0.001), higher pathologic T (pT) stages (P = 0.024), and biochemical recurrence (BR) (P = 0.002). The difference in AQP-3 and AQP-5 expression between neoplastic and non-neoplastic tissues was not established and there were no correlations with clinicopathological parameters. AQP-1 overexpression was evident in tumors with higher GS, it was less evident in tumors with lower GS, and it was associated with BR and a higher pT stage. AQP-1 overexpression is associated with prostate cancer progression.