TSC1 and neoplasm: Typically, metformin inhibits the mTORC1 complex through the phosphorylation of RAPTOR (regulatory-associated protein of mTOR) via AMPK.[21] Metformin also blocks the tumor suppressor genes, TSC1, and TSC2, through the IGF1 and insulin signaling pathway, thereby exerting an inhibitory effect on mTORC1.