Estrogen receptors in male breast cancer: clinical and pathologic correlations.

Breast cancer tissue from 12 male patients was evaluated for the presence of estrogen receptors (ER), and at least 10 of 12 were found to be high in ER (ER+). A combination of previously published cases and our own experience indicates that 80% of patients (37/47) have ER+ tumors. This incidence of ER positivity in men is greater than that in women with breast cancer. Clinical responses to hormonal therapy have been observed in the ER+ patients but not in one ER--patient. Measurement of ER may be clinically important in men with breast cancer.