MTOR and neoplasm: Metformin, an agent for type 2 diabetes, showed the anti-tumor activity in various types of tumors, and the therapeutic effects were mainly attributable to inhibition of the mammalian target of rapamycin (mTOR) pathways through AMP-activated protein kinase (AMPK) and others molecules such as regulated in development and DNA damage responses 1 (REDD1) [4].