Several basic researches also demonstrated that metformin inhibited cancer cell proliferation, metabolism, and angiogenesis through activation of adenosine monophosphate-activated protein kinase (AMPK) and inhibition of mammalian target of rapamycin (mTOR) signaling pathway.17–19 Metformin may have multiple activities against tumor, which represent a promising perspective in cancer therapy.20 To date, though the antineoplastic effects of metformin are biologically plausible, existing data remain controversial. The gene discussed is MTOR; the disease is neoplasm.