BECN1 and neoplasm: Studies have shown that the autophagy level in certain tumor cells is lower than in normal cells, even in the case of hypoxia or nutritional deficiency, and the autophagy level cannot be enhanced due to monoallelic deletion of the BECN1 gene, such as in breast cancer, ovarian cancer, and prostate cancer cells; however, for most tumor cells or advanced cancer cells, a higher level of basic autophagy is needed to meet the higher metabolic demands [20,21,22].