MTOR and breast cancer: A sensitization screening, aimed at identifying compounds that synergize with Palbociclib in HR+ BC cell lines, revealed that several cytotoxic chemotherapy drugs (paclitaxel, camptothecin, vinorelbine, etc) showed an antagonistic interaction, while PI3K- (GDC-0941), AKT- (MK2206), mTOR- (Everolimus) and IGF1R-inhibitors displayed a synergistic effect (23).