MDM2 and cancer: Due to the inhibition of protein-protein interactions between MDM2 and several of its binding partners including p53, p73α (another tumor suppressor involved in cell cycle regulation and induction of apoptosis with structural resemblance to p53), transcription factor E2F1 (involved in cell cycle and action of tumor suppressor proteins) and Hif-1α (hypoxia inducible factor 1α) [113–115], the use of nutlin-3a led to the activation of several pathways associated with anti-cancer effects [110].