Estrogen receptor activity is clinically useful in predicting

The likelihood of response of a breast cancer to hormonal therapy is dependent on the presence of hormone receptors in the cytoplasm of the breast cancer cells. Receptors for corticosteroids, progesterone, prolactin, and estrogen have been identified. Eighty percent of patients with tumors that exhibit receptors to both estrogen and progesterone respond favorably to hormonal manipulation. Estrogen receptor activity has no predictive value in diagnosing ovarian cancer or metastatic disease, forecasting the development of osteoporosis, or determining the likelihood of a beneficial response to chemotherapy.