Expression of aquaglyceroporins in epithelial ovarian tumours and their clinical significance.

Protein levels of aquaglyceroporins AQP3, AQP7 and AQP9 were measured by immunohistochemistry and Western blotting in epithelial ovarian tumour tissue from 98 patients and in normal ovary tissue from 20 persons with uterine myoma. AQP3 and AQP9 proteins were detected immunohistochemically in the basolateral membranes of benign and borderline tumour cells and were found to be distributed throughout the plasma membranes of malignant tumour cells. AQP7 protein was localized in the plasma membranes of benign tumour cells but, in borderline and malignant tumour cells, it was selectively stained in the nuclear membrane. Western blotting showed significantly higher AQP7 and AQP9 protein expression in malignant and borderline tumours than in benign tumour and normal ovarian tissue. AQP9 expression level was positively and significantly correlated with tumour grade and histological type. It was concluded that a high level of aquaglyceroporin expression may be an important factor in ovarian carcinogenesis.