Increased androgen receptor expression in estrogen receptor-positive/progesterone receptor-negative breast cancer.

Expression of estrogen receptor alpha (ER) and/or progesterone receptor (PR) defines luminal breast cancer. Even though androgen (AR) and glucocorticoid receptors (GR) are highly expressed in luminal breast cancers, prognostic value remains uncertain and concomitant expression of these four hormone receptors is still unexplored. Here, we evaluated ER, PR, AR, and GR expression, using immunohistochemistry, in a cohort of 169 breast cancer patients and correlated these findings with clinical and pathological parameters. We found that AR is more frequently expressed and at higher levels in the ER+PR- subset compared to ER+PR+ tumors. There were no significant differences in GR expression between tumor subsets. Moreover, most luminal tumors also expressed either AR or GR and most basal tumors were also negative for AR and GR. These data suggest that targeting AR in ER+PR- tumors may represent a promising therapeutic alternative in hormonal refractory tumors.