Estrogen and progesterone receptors in human breast cancer. Correlation with histologic subtype and degree of differentiation.

Microscopic review of 490 consecutive human breast biopsy and mastectomy specimens were correlated with estrogen and progesterone receptor content of the tissue, by subtype and degree of differentiation. Of the 4 grades of differentiation, the less differentiated Grade III and IV tumors showed significantly lower levels of estrogen and progesterone receptors in infiltrating ductal and lobular carcinoma (P less than 0.001). In contrast, patients with medullary carcinoma had the lowest tissue levels of estrogen and progesterone receptors with approximately 80% of the cases with less than 10 fmol/mg protein. Patients with mucinous carcinoma had the highest percentages of positive estrogen and progesterone receptor levels (75% and 87%, respectively). Sixty-three percent of the patients with Grade IV infiltrating ductal carcinoma were younger than 53 years of age (P less than 0.001). Patients younger than 53 years of age with Grade II and III infiltrating ductal carcinoma also had significantly lower levels of estrogen receptors, but not of progesterone receptors, than those patients older than 53 years of age (P less than 0.001). Nineteen of 20 "normal" breast tissue specimens were negative (less than 3 fmol/mg protein) for estrogen and progesterone receptors. About 50% of 17 tissue specimens from benign breast lesions (fibroadenoma, fibrocystic disease, sclerosing adenosis) showed positive estrogen (greater than 10 fmol/mg protein) or progesterone receptor values. In two patients with gynecomastia, no estrogen or progesterone receptors were detectable.