Estrogen receptors in male breast cancer.

Estrogen receptor assays were performed on tumor specimens from 6 male patients with documented breast cancer. Five out of six (83%) males had positive ER assays with values ranging from 23-384 femtomoles per mg cytosol protein. A review of the literature showed that 32 out of 38 patients (84%) reported were positive for estrogen receptor. Four out of five ER positive males responded to orchiectomy. Estrogen receptors are present in a high percentage of males with breast cancer and may predict response to treatment, similar to female breast cancer.