FAS and cancer: There have been numerous reports describing the localization of caspase-3 mainly as cytosolic and nuclear,10,37 a few reports on caspase-3 localized to the mitochondria32,33 and one report indicating active caspase-3 found in the ER of rabbit hippocampus upon aluminium-induced neurotoxicity.38 Furthermore, caspase-7 was reported to be localized in the ER following anti FAS treatment in mouse liver.39 Therefore, ER localization of active caspase-3 is supported by literature precedence but is now detected for the first time in cancer cells.