Estradiol receptor assays in normal and neoplastic tissues. A possible diagnostic acid for tumor differentiation.

Estradiol (E2) binding activity was studied in several normal tissues and neoplasias of humans and experimental animals. Positive E2 binding was seen in 37 percent of breast primary malignancies, 50 percent of breast cancer metastasis to other organs, and 55 percent of breast cancer metastasis to lymph nodes. Two other tumors, renal cell carcinomas and thyroid adenocarcinomas, also had a high percent of E2 binding activity. No difference was evident histologically between the tumors which were positive and those which were negative. Elevated E2 binding activity was seen in normal liver and pancreas of rats and mice as well as in an experimentally induced acinar pancreatic carcinoma of the rats. These preliminary results indicate that the measurement of estradiol receptors should be extended to other neoplasias than breast cancer, and it may give some indication about the evolution and the hormonal controls of the tumors themselves.