Unfolded protein response, a link between endometrioid ovarian carcinoma and endometriosis: A pilot study.

The aim of the present study was to analyze the expression profile of unfolded protein response (UPR) genes in endometrioid ovarian carcinoma and to evaluate its possible involvement in the neoplastic progression of endometriosis. An experimental retrospective pilot study was conducted on women with a diagnosis of endometrioid ovarian carcinoma at FIGO stage IA, ovarian endometriotic cysts or healthy subjects without a previous diagnosis of endometriosis. The expression profiles of UPR genes (ATF6, GRP78, CHOP and XBP1) were compared among ovaries with endometrioid ovarian cancer, endometriotic ovarian cysts, healthy contralateral ovaries and eutopic and healthy endometrial tissues. A significantly higher expression of ATF6 and GRP78 was detected in the affected ovaries in comparison with the healthy contralateral ovaries, while CHOP and XBP1 exhibited a significantly lower expression. XBP1 was overexpressed in endometrial tissues and its expression gradually decreased in endometriosis cysts and endometrioid ovarian carcinoma. These results support the hypothesis that alterations in the UPR genes CHOP and XBP1 are involved in the neoplastic progression of endometrioid ovarian cancer and are acquired following ovarian localization of ectopic endometrial cells.