MTOR and colonic neoplasm: Various in vitro and in vivo studies have documented that metformin induces anticancer effect mainly by mediating 5’adenosine monophosphate (AMP)-activated protein kinase (AMPK)/mammalian target of the rapamycin (mTOR) pathway and insulin/ insulin-like growth factor-related pathways that modulate inflammation and inhibit colon tumor development and growth [31, 37, 56, 57].