Although this proposal was recently challenged and the tumor suppressive functions of Beclin1 remain controversial [20], diverse mouse models with defects in the autophagy machinery caused by whole-body or tissue-specific, heterozygous, or homozygous knockout of Atg genes show increased incidence of some malignancies or increased susceptibilities to carcinogens [10, 12]. This evidence concerns the gene BECN1 and neoplasm.