Immunohistochemical localization of aromatase and apoptosis-associated proteins in ovarian serous cystadenocarcinoma arising from ovarian endometriosis.

ABSTRACT

An immunohistochemical study was made of a case of serous cystadenocarcinoma that had been shown to have arisen from ovarian endometriosis. Aromatase cytochrome P450 (P450arom), an enzyme responsible for estrogen biosynthesis, was localized in the epithelial linings of the endometriosis and faintly in the transitional part, whereas it was not expressed in the carcinoma tissue. In contrast, estrogen receptors, progesterone receptors, and apoptosis-associated proteins, Fas, Fas ligand, and Bax were expressed in both endometriosis and carcinoma tissues of the tumor, whereas Bcl-2 was not expressed in either tissue of the tumor. It was suggested that the undifferentiated shift of the histologic grade might result in the loss of P450arom and that the malignant transformation was not caused by an altered balance of apoptosis-associated proteins. Accumulation of these studies may lead to a better understanding of the nature of malignant transformation of ovarian endometriosis.