FOXA1 is expressed in ovarian mucinous neoplasms.

FOXA1 is a transcription factor essential for the binding and action of other transcription factors on the chromatin. It is the major regulator of endoderm differentiation. It has important roles in breast, prostate and endometrial cancer. It has never been studied in ovarian tumours. The aim of this study was to investigate its expression in ovarian epithelial neoplasms. A total of 195 primary ovarian epithelial borderline or malignant tumours were immunohistochemically studied for the expression of FOXA1. Nineteen percent of the tumours strongly and diffusely expressed FOXA1. Of these, 75.7% belong to the mucinous category (p < 0.0001). Seventy-five per cent of mucinous borderline tumours and 46.7% of mucinous carcinomas overexpressed FOXA1. Brenner tumours also expressed FOXA1. FOXA1 was rarely expressed in serous (6/115) and endometrioid tumours (1/11). Clear cell tumours were completely negative (0/16). Of normal structures, ciliated tubal cells, Walthard nests and transitional metaplasias of the tubal-mesothelial junction, all strongly expressed FOXA1. In conclusion, FOXA1 is found in ovarian mucinous and Brenner tumours.