FAS and colorectal carcinoma: To our knowledge, this is the first study to: a) simultaneously evaluate the effect of tumor cell irradiation on multiple common death receptors (Fas, TRAILR, LTβR and TNFR1), as well as the intracellular sensitizers to death in numerous colorectal carcinoma cells lines in a single study, b) evaluate multiple sub-lethal doses, and c) evaluate the longevity or sustainability of these changes.