MTOR and cancer: To date, potential drug resistance mechanisms have analyzed following aspects5: epithelial-mesenchymal transition (EMT)29, biological processes (tumor microenvironment, angiogenesis, inflammation, fibrosis, hypoxia, oxidative stress, autophagy, and viral reactivation)8, 30, 31, 32, aberrant signaling activation (EFGR or mTOR signaling pathway)31, 33, and, presence of cancer stem cells (CSCs)34.