Estrogen receptor protein in visceral metastases from breast carcinoma.

Estrogen receptor protein assays were done on 1,243 tissue specimens, 34 of which represented metastases from primary breast carcinoma to parenchyma of liver, lung or brain. Eight of these specimens contained significant amounts of estrogen receptor protein. Most (4 of 5 evaluable cases) of the ERP-positive patients responded to endocrine ablation, as compared with 13 percent (2 of 16 evaluable cases) of the ERP-negative patients. We conclude that biopsy of liver and lung metastases may be useful in some circumstances and that endocrine manipulation frequently provides palliation when these metastases are ERP-positive.