Is 1,4-dioxane a genotoxic carcinogen?

Female Sprague-Dawley rats were given 0, 168, 840, 2550 or 4200 mg/kg of 1,4-dioxane 21 and 4 h before sacrifice. Hepatic DNA damage (by the alkaline elution technique), ornithine decarboxylase activity (ODC), reduced glutathione content, cytochrome P-450 content and serum alanine aminotransferase activity (ALT) were determined. Treatment with 1,4-dioxane increased hepatic DNA damage and cytochrome P-450 content at doses of 2550 and 4200 mg/kg. Large increases in the activity of hepatic ODC were observed at 840, 2550 and 4200 mg/kg of 1,4-dioxane. Thus the data suggest that 1,4-dioxane is a weak genotoxic carcinogen in addition to being a strong promoter of carcinogenesis (a non-genotoxic carcinogen).