Ninety-five ovarian neoplasms were studied for ER and PR content by immunohistochemistry, and the results were compared to those of biochemical ER and PR determination in 89 cases. While there was no difference between the results of both methods of hormone receptor determination in the few non-epithelial tumors studied, there was only a low correlation between the semi-quantitative results of ER and PR immunohistochemistry, and the corresponding values of biochemical steroid receptor determination in 77 common epithelial carcinomas of the ovary. In a majority of cases with discordant results between both methods, tumors were hormone receptor positive by DCC analysis but negative by immunohistochemistry. The finding of ER or PR positive stromal cells without any evidence of hormone receptor positive epithelial tumor cells in such tumors offers a possible explanation for the apparent discrepancy. Ovarian carcinomas containing ER or PR positive epithelial tumor cells may constitute a smaller subgroup of all tumors thought to be hormone receptor positive when only results of biochemical methods of steroid receptor determination were available.
