PRF1 and cancer: Hotspots in cancer co-localized with genes that are enriched for extracellular glycoproteins, G-protein coupled receptors especially olfactory receptors, cell-cell adhesion, molecular species intrinsic to the plasma membrane, Ig- and EGF-like domains, ligand gated ion channels, membrane attack complex component/perforin, complement 9, cadherin, Sushi domains, potassium channels, Kazal proteinase inhibitors, fibronectin III, glycosylation, glycoproteins, the machinery to hydrolize and excrete proteins, and finally MHCI and MHCII.