Detection of the estrogen receptor and response to endocrine therapy in male breast cancer patients.

The estrogen receptor was measured in breast cancer of two male patients. Both patients had a positive receptor content in their tumors. The dissociation constant and number of binding sites were both very similar to those in the female counterpart. In one of the patients, the number of binding sites in the metastatic lesions of the liver was similar to that in the primary site. The patient responded well to the endocrine ablation therapy with a remission period of 8 months. The estrogen receptor was found to be positive in 12 out of 14 cases of male breast cancer reported previously including the present 2 patients. Three out of 4 cases with positive receptor contnet, including the present case, responded to orchiectomy.