MTOR and neoplasm: One of the leading ways in which metformin exerts its anti-tumor effect is via the AMP-activated kinase signaling network, where it suppresses malignancy through the inhibition of cellular proliferation and division via the suppression of the downstream mammalian target of rapamycin (mTOR)-signaling pathways and the AMP-activated protein kinase axis, which induces apoptosis and autophagy of cancer cells [54].