BECN1 and cancer: Surprisingly, these studies demonstrate that the depletion of essential autophagy-relevant gene products such as autophagy related (ATG) 5 or beclin 1 (BECN1) [1–3], although increase the cancer cytotoxic effect of therapy in vitro and in vivo in immune deficient mice, reduce the efficacy of radiotherapy or chemotherapy in immune competent mice [23] (Fig. 1a).