PAWR and cancer: Downregulation of Par-4 is considered to be critical for tumorigenesis as it is downregulated in various human cancers including prostate cancer (CaP).22 Par-4 knockout mice spontaneously develop tumors in various organs21 and exhibit prostatic intraepithelial neoplasia.23 In order for endogenous levels of Par-4 in normal and cancer cells to cause apoptosis, an additional stimulus is required.24, 25, 26