The PI3K/AKT/mTOR pathway, the most crucial upstream signalling pathway of autophagy, is well established as a regulator of a wide range of cellular processes that mediate cell survival and death, and this pathway is inhibited by malnutrition, hypoxia, external pressure or other stress conditions to suppress cell proliferation and enhance autophagy, eventually leading to cell death.38, 39. The gene discussed is MTOR; the disease is malnutrition.