For example, the recent findings of Zhou et al. [81] suggested that OGG1 Ser326Cys polymorphism may be a risk factor for lung, digestive system and head and neck cancers; nevertheless, no association was observed in breast, prostate and bladder cancers, and the association between OGG1 Ser326Cys polymorphism and the susceptibility of digestive system cancers was found to only exist in Asian populations. This evidence concerns the gene OGG1 and digestive system cancer.