In the seven years since the first clinical correlations were reported from our laboratory, the utility of estrogen receptor assays on excised tumor tissue has become well established as an aid in deciding which patients with advanced breast cancer should be treated by endocrine ablation (oophorectomy, adrenalectomy, hypophysectomy) or by hormone administration, and which should be placed directly on chemotherapy. The experience of many investigators1 has confirmed the original conclusion that patients whose tumors contain no detectable estrogen receptor protein (estrophilin) have little chance of benefit from endocrine therapy, whereas most, but not all, women with receptor-containing breast cancers will respond favorably to endocrine manipulation.
Recent evidence,2 though still limited, indicates that estrophilin analyses of stage I and stage II primary tumors can be used to predict response to endocrine therapy when disseminated disease appears at a later time. These observations, if confirmed, suggest the value of routinely
Jensen EV. Estrogen Receptors in Human Cancers. JAMA. 1977;238(1):59-60. doi:10.1001/jama.1977.03280010059026