In experimental models of gastric cancer, the approved proteasome inhibitor bortezomib, the nonapproved indirect inhibitor of cullin-RING E3 ligases MLN4924 (pevonedistat) and small molecule inhibitors of the E3 ligase MDM2 nutlin-3 and APG-115 have demonstrated anti-proliferative effects and could prospectively supplement conventional chemo- and radiotherapy [153–155]. The gene discussed is MDM2; the disease is gastric cancer.