Dual PI3K/mTORis (BKM120, BYL719, RAD001 and BEZ235) also exert strong anti-proliferative effects on a range of ER+/human epidermal growth factor receptor 2 (HER2)+ BC cell lines carrying PI3KCA mutations both in vitro and in vivo [138]. This evidence concerns the gene ERBB2 and breast cancer.