Steroidogenic factor-1 expression in ovarian endometriosis.

Steroidogenic factor-1 (SF-1), a major protein regulating the complex cascade of steroidogenis, has been postulated to play a role in ovarian endometriosis. However, the expression in situ of SF-1 in ovarian endometriosis is unknown. To shed light on its presence, the expression of SF-1 was studied by immunohistochemistry in 30 cases of ovarian endometriosis (proliferative, n = 15; secretory phase, n = 15) and in 10 cases of normal eutopic endometrium coming from the same patients. No SF-1 immunoreactivity was observed in glands or endometrial stroma from ovarian endometriosis or eutopic endometrium. In contrast, a strong immunoreactivity was observed in the adjacent ovarian cortical or medullary mesenchymatous cells in all the cases examined independently of the cycle's phases. Contrary to the earlier reported hypothesis, our data showed for the first time the absence of SF-1 expression in glands and endometrial stroma from ovarian endometriosis and eutopic endometrium. However, the strong expression of SF-1 observed in cortical and medullary ovarian mesenchymatous cells adjacent to endometriosis, suggests a potential role for these cells in locally induced steroidogenesis.