[Immunohistochemical study on estrogen receptors in conventionally formalin-fixed, paraffin-embedded tissues of...

Using specific monoclonal antibody to human estrogen receptors (ER), monoclonal antibody H222, with an avidin-biotin-peroxidase complex method, immunohistochemical localization of ER was performed on formalin-fixed, paraffin-embedded tissues of 42 endometrial carcinomas. The paraffin sections were preceded by trypsin treatment to expose antigenic sites. Immunohistochemical evaluation incorporated both the intensity and distribution of staining into a semiquantitative analysis. Specific staining for ER was observed only in the nuclei of epithelial, stromal and malignant cells. No specific cytoplasmic staining was observed in all paraffin sections. ER-positive staining [histologic score (H-score) > or = 75] was found in 23 (54.8%) of 42 samples and the ER H-Score of cancer components was significantly associated with the histological grade of endometrial carcinomas (P < 0.05). The ER-positive patients tended to have a better prognosis than ER-negative ones. Thus, it may be concluded that the treated formalin-fixed, paraffin-embedded tissues are still suitable for detecting ER by the immunohistochemical method, and the ER content of endometrial carcinomas is useful in indicating the differentiation of cancer and in predicting the patient's prognosis.