Pathological review of breast lesions analyzed for estrogen receptor protein.

This report provides a detailed pathological review of 333 specimens analyzed for estrogen receptor protein (ERP) and correlates a series of morphological features with ERP results. Included were 147 primary breast carcinomas, 78 metastases, 27 fibroadenomas, and 81 nonneoplastic tissues, all from women. ERP in cytosols was assayed by incubation with [3H]estradiol in the presence and absence of "cold" estradiol followed by dextran-charcoal treatment. Results were summarized as positive (greater 60% inhibition by nontritiated estradiol, greater than 10 fmoles/mg protein), negative (less than 60% inhibition by nontritiated estradiol, less than 10 fmoles/mg protein), or intermediate borderline combinations. ERP in primary tumors ranged from 0.2 to 358 fmoles/mg protein (54.4% positive, 35.4% negative, 10.2% borderline). New findings are: (a) a high frequency of positive ERP in invasive lobular carcinoma (12 of 13, 92.3%) compared to typical ductal tumors (64 of 117, 54.7%); and (b) low frequency of positive ERP(5 of 21, 23.8%) in tumors with a prominent local lymphocyte reaction. Three ERP-positive noncarcinomatous specimens were fibroadenomas of high epithelial cellularity from patients under 30 years. No statistically significant relationship existed between ERP and any other morphological features that were examined.