RIGI and prostate cancer: However, RIG-I signaling in pancreatic and prostate cancer cells robustly induces expression of several factors that activate the extrinsic apoptotic pathway, including Fas, Fas Ligand, Tumor Necrosis Factor (TNF), TNF-related apoptosis-inducing ligand (TRAIL), and the TRAIL receptors Death Receptor (DR)-4 and DR-5, causing caspase-8 activation and extrinsic apoptosis.