AR and breast cancer: In fact, it is estimated that up to 90% of primary BC and up to 75% of metastatic lesions expressed AR (Hickey et al., 2012), as well as in the 50–80% of invasive BCs and in the 85% of ductal carcinoma in situ (DCIS) (Lim et al., 2014), although among the BC subtypes the frequency appears variable.