Concise summary of relation between autophagy and tumor growth. Autophagy can be induced by different metabolic stressors in the tumor microenvironment including hypoxia, nutrient deprivation, inflammation and ECM detachment. Autophagy can be activated in different cells at different stages of tumor growth and have paradoxical roles in tumor growth. Before tumorigenesis, autophagy promotes normal cells survival and suppresses tumorigenesis. In contrast, after tumorigenesis, autophagy promotes survival of the cancer cells and thus promotes tumor growth.