MTOR and neoplasm: Metformin activates AMPK after the inhibition of ETC I, inhibits the expression of mTOR and further inhibits the expression of more important factors mediating downstream pro-carcinogenic pathways and the process of tumor development, such as nuclear factor kappa B (NF-κB), interleukin-6 (IL6), mitogen-activated protein kinase (MAPK), Ras and c-MYC [91,92,93].