Protective role of autophagy during early and late stages of tumorigenesis. Before incipient tumor cell formation, autophagy protects genomic stability through retarding stem cells-involved damage/repair cycle, and inhibits inflammatory microenvironment formation, thus preventing incipient tumor cell formation. After incipient tumor cell formation, autophagy also protects tumor cells survival by decreasing metabolic damage and increasing cellular metabolic supply. Meanwhile, autophagy promotes anoikis resistance and dormancy for providing favorable condition for tumor metastasis. In a word, autophagy protects normal cells or tumor cells during the early or late stage of tumorigenesis, respectively.