Three randomized, placebo-controlled, phase III trials are evaluating the mTOR inhibitor, everolimus, in the following combinations: with trastuzumab and paclitaxel as first-line therapy in HER2-positive MBC (Breast cancer trial of OraL EveROlimus (BOLERO) 1); with exemestane in postmenopausal women with ER-positive MBC who are refractory to letrozole or anastrozole (BOLERO 2), and with trastuzumab and vinorelbine in women with HER2-positive MBC who are resistant to trastuzumab and have been pretreated with a taxane (BOLERO 3). Here, ERBB2 is linked to breast cancer.