Estrogen and progesterone receptors in epithelial ovarian malignancies

Cytoplasmic estrogen receptor levels (ER) were measured in ovarian epithelial malignancies from 44 patients using a dextran-coated charcoal assay with analysis of the data by Scatchard plots. In 31 cases, progesterone receptor levels (PR) were also determined. In untreated patients, 68.8% of malignancies were ER-positive (greater than or equal to 10 fmole receptor/mg protein) and 35.0% were PR-positive (greater than or equal to 50 fmole/mg protein). Receptor levels in ovarian epithelial malignancies were not dependent on patient age, menopausal status, tumor stage, or histologic grade. However, ovarian endometrioid carcinomas contained significantly more PR than other histologic variants (P less than 0.02). Excluding endometrioid carcinoma, tissues from patients treated with chemotherapy contained less ER and PR than tissues from untreated patients. ER-positive tumors from three patients assayed before cyclophosphamide or combination chemotherapy became ER-negative after therapy. In addition, tamoxifen increased cytoplasmic PR (124 to 333 fmol/mg) and decreased cytoplasmic ER (65 to 4 fmol/mg) in a single patient with endometrioid carcinoma.