Endometrial cancer: histologic correlates of immunohistochemical localization of progesterone receptor and estrogen receptor.

Progesterone and estrogen receptor localization, using monoclonal anti-receptor antibodies JZB39 and H222, was studied in 105 endometrial adenocarcinomas. Immunohistochemical evaluation incorporated both intensity and distribution of staining. Both anti-progesterone receptor and anti-estrogen receptor localized in the nucleus of target cells. Significant levels of progesterone receptor and estrogen receptor were seen localized in stromal and myometrial elements that diverged from the malignant epithelial component. Analyses of endometrial adenocarcinomas with anti-progesterone receptor and anti-estrogen receptor antibodies correlated with histologic differentiation. The ability to define divergent receptor populations in stromal and myometrial elements versus malignant epithelial elements indicates that immunohistochemical assay of progesterone and estrogen receptor provides information complementary to that from conventional quantitative ligand binding assays.