2-Amino-3,8-dimethylimidazo-[4,5-f]-quinoxaline (MeIQx) is a food-derived carcinogen that has been found in high temperature-cooked fish and meats.1 It is activated by hydroxylation and subsequent O-acetylation via the cytochrome P450 (CYP) isoform CYP1A2 and N-acetyltransferase 2, respectively, in UV5 cells expressing the human enzymes to a metabolite that reacts with DNA to form adducts.2 MeIQx (200 and 400 ppm in the diet) induces tumor formation in rats.3
1.Johansson, M.A., and JÄgerstad, M.Occurrence of mutagenic/carcinogenic heterocyclic amines in meat and fish products, including pan residues, prepared under domestic conditionsCarcinogenesis15(8)1511-1518(1994) 2.Metry, K.J., Neale, J.R., Doll, M.A., et al.Effect of rapid human N-acetyltransferase 2 haplotype on DNA damage and mutagenesis induced by 2-amino-3-methylimidazo-[4,5-f]quinoline (IQ) and 2-amino-3,8-dimethylimidazo-[4,5-f]quinoxaline (MeIQx)Mutat. Res.684(1-2)66-73(2010) 3.Kushida, H., Wakabayashi, K., Sato, H., et al.Dose-response study of MeIQx carcinogenicity in F344 male ratsCancer Lett.83(1-2)31-35(1994)