Estrogen and progesterone receptor content of endometrial carcinomas: comparison of total tissue versus cancer component analysis.

Estrogen (ER) and progesterone (PgR) receptor values in 105 endometrial carcinomas were compared using immunocytochemical and standard biochemical techniques. Peroxidase-antiperoxidase staining for location of anti-ER (H222) and anti-PgR (JZB39) primary antibodies was used to generate a semiquantitative (HSCORE) assessment of receptor content in tissue components and the total specimen. Both total HSCORE and cancer component HSCORE correlated with log biochemical assay values for ER and PgR. Biochemical assay values, total HSCORE, and cancer component HSCORES all demonstrated internal correlations between ER and PgR levels. Correlation was somewhat closer for cancer component HSCORE values of ER and PgR than the values for total tissue HSCORE. When receptor content was analyzed by histologic grade, all three estimates of receptor status demonstrated a decreasing proportion of ER and PgR positive lesions with decreasing histologic differentiation; however, the proportion of receptor negative lesions in grade 3 lesions was much higher when using total HSCORE or cancer component HSCORE than when using biochemical assay values (P less than 0.005. Immunocytochemical techniques for localization of ER and PgR in endometrial carcinoma specimens may allow a more focused evaluation of the receptor content in the malignant elements than standard biochemical techniques.