For example, Silvestri et al. demonstrated that metformin-induced cell death in breast cancer cell lines (MCF-7, SKBR3, and MDA-MB-231) was significantly mitigated in high-glucose conditions (12.5 mM and higher); however, this did not affect the metformin-induced down-regulation of mTOR [27]. Here, MTOR is linked to breast carcinoma.