On the other hand, different chimeric E3 ubiquitin ligases, by fusing an “interacting domain” with an “E3 catalytic domain”, have been reported to specifically degrade cancer-causing proteins, including β-catenin [46], KRAS [47] and ErbB1-3 [44], thus successfully inhibiting the related tumor growth in cultured cells and animal models. This evidence concerns the gene KRAS and neoplasm.