MTOR and cancer: Metformin-induced inhibition of the mTOR pathway has been demonstrated in different types of cancer, such as leukemia [30, 32, 59, 60], lung cancer [61, 62], breast cancer [63, 64], oral squamous cell carcinoma [65], lymphoma [36], and thyroid cancer [35, 66] in human, as well as in both papilloma and squamous cell carcinoma in mice [67].