**2. Aminoazo dyes and 8-oxo-Gua / OGG1**

Food factors have been extensively investigated in association with oxidative DNA damage and its repair systems. Some food factors, such as aminoazo dyes, are known inhibitors of OGG1 expression. Aminoazo dyes were previously used as artificial color additives to food. Some of them, such as *N*-methyl-4-aminoazobenzene, *N*, *N*-dimethyl-4-aminoazobenzene, and 3'-methyl-4-dimethylaminoazobenzene (3'-MeDAB), are hepato-carcinogenic. We previously analyzed the effects of 3'-MeDAB on 8-oxo-Gua repair systems in rodent livers, and reported that 3'-MeDAB increased 8-oxo-Gua generation and decreased OGG1 expression, possibly by cleaving the protein [22]. These results suggested that the liver carcinogenicity of 3'-MeDAB was due to an increase in 8-oxo-Gua generation via 3'-MeDABinduced downregulation of OGG1 expression.

The use of 3'-MeDAB as a food additive is now prohibited. However, other types of azo dyes are still being used. Therefore, more research is needed to define the effects of azo dyes on human health.
