PEG3 induces apoptosis in cooperation with SIAH1A and acts as a mediator between TP53/p53 and BAX in a neuronal death pathway that is activated by DNA damage. PEG3 acts synergistically with TRAF2 and inhibits TNF induced apoptosis through activation of NF-kappa-B. PEG3 also possesses a tumor suppressing activity in glioma cells.