TP53-regulated inhibitor of apoptosis 1 (TRIAP1, also known as p53 cell survival factor or p53CSV), is a small 76 amino acids long, evolutionarily conserved protein. TRIAP1 is a novel apoptosis inhibitor that binds HSP70 in the cytoplasm and blocks the formation of the apoptosome and caspase-9 activation. TRIAP1 is reported to be associated with resistance of apoptosis in different human malignancies. TRIAP1 is a pathway-specific regulator of the cellular response to p53 activation. Mechanistically, TRIAP1 modulates the apoptotic pathways through interaction with HSP70, inhibition of the interaction of cytochrome c with the apoptotic protease activating factor 1 and activation of the downstream caspase-9, thus resulting in increased resistance by inhibiting apoptosis and permitting DNA damage repair.