Author information Laboratory of Experimental Pathology, National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, NC 27709, USA. nyska@niehs.nih.gov Abstract The Tg.AC mouse carrying the v-Ha-ras structural gene is a useful model for the study of chemical carcinogens, especially those acting via non-genotoxic mechanisms. This study evaluated the efficacy of the non-toxic, water-soluble antioxidant from spinach, natural antioxidant (NAO), in reducin