Abstract: As a pro-apoptotic factor, prostate apoptosis response protein 4 (par-4) was first found in the male
hormone-dependent prostate cells (AT-3). Endogenous Par-4 sensitizes cancer cells to apoptotic stimuli, but exogenous Par-4
selectively induces apoptosis in cancer cells, and these activities depends on the structure of its core domain SAC. Par-4 and
SAC can specifically induce apoptosis of cancer cells but not of normal cells, and are therefore potential anti-cancer drugs. In
this review we summarize the discovery, structure, and function of par-4, and its intracellular signaling pathways, then discuss
the application prospects of Par-4 and SAC in the clinical treatment of cancer and the problems in its research and clinical
applications .