Estrogen receptors and antiestrogen therapy in selected human solid tumors.

Tumor biopsies from a range of human cancers not normally thought to be hormone-dependent were assayed for the presence of both cytoplasmic and nuclear estrogen receptors, using strict criteria of specificity and affinity. Of 72 tumor samples assayed, only one had both cytoplasmic and nuclear receptors. However, several others showed the presence of estrogen-binding components with characteristics different from those of the normal human estrogen receptor. Thirty patients with advanced, measurable disease were treated with the antiestrogen tamoxifen. In only 25 of these was the response evaluable, and in each case, the disease progressed. This study suggests that the occurrence of the classic estrogen receptor in human cancers, other than breast and uterine, is rare; this finding is supported by the absence of response of advanced disease to antiestrogen treatment.