First and second generation mTOR inhibitors. A. First generation mTOR inhibitors (Rapamycin and Rapalogs): Ⅰ) Sirolimus, Ⅱ) Everolimus, Ⅲ) Deforolimus, Ⅳ) Temsirolimus. B. Second generation mTOR inhibitors: Ⅴ) MLN0128 (Sapanisertib), Ⅵ) CC-233, Ⅶ) NVP-BEZ235 (Dactolisib), Ⅷ) AZD-8055. Chemical structures of the drugs were obtained from the PubChem website (https://pubchem.ncbi.nlm.nih.gov).