Association between OGG1 Ser326Cys polymorphism and risk of upper aero-digestive tract and gastrointestinal cancers: a meta-analysis

Abstract

Cancers of the upper aero-digestive and gastrointestinal tract are one of the major causes of mortality around the world. DNA repair genes play a vital role in preventing carcinogenesis by maintaining genomic integrity. Polymorphisms in the nucleotide sequence of DNA repair genes are often reported to be associated with an increased risk for different cancers. The OGG1 gene encodes the enzyme 8-oxoguanine DNA glycosylase which removes oxidatively damaged bases of DNA. Several studies report that the OGG1 Ser326Cys polymorphism increases the risk for cancers of the upper aero-digestive and gastrointestinal tract. However, other studies provide evidence that such an association does not exist. A meta-analysis to assess the role of OGG1 Ser326Cys polymorphism in the cancers of the upper aero-digestive and gastrointestinal tract was therefore undertaken in order to resolve this ambiguity. Seventeen studies were recruited for this meta-analysis after screening 58 articles with a total of 5533 cases and 6834 controls for which the odds ratio with 95 % confidence interval was calculated. Begg's funnel test and Egger's test were performed for calculating publication bias. Our study reveals an association between OGG1 Ser326Cys polymorphism and cancer susceptibility of the upper aero-digestive and gastrointestinal tract (CG + GG vs CC; odds ratio, OR 1.22; 95 % CI 1.05-1.41; GG vs CG + CC; OR 1.36; 95 % CI 1.09-1.70; GG vs CC; OR 1.46; 95 % CI 1.12-1.92). Subgroup analysis based on cancer types and ethnicity also revealed the association of OGG1 Ser326Cys polymorphism to the risk for upper aero-digestive and gastrointestinal tract cancers among both the Asian and the Caucasian populations. No risk was however observed for smoking habits and OGG1 Ser326Cys polymorphism. In conclusion, OGG1 Ser326Cys polymorphism may be associated with the increased risk for aero-digestive tract and gastro-intestinal cancers in both Asian and Caucasian populations.

Keywords: Gastrointestinal; Meta-analysis; OGG1; Upper aero-digestive tract.

Fig. 1

Flow chart showing the procedure of literature selection

Fig. 2

Figure showing forest plots of OGG1 Ser326Cys polymorphism in association with upper aero-digestive tract cancer and gastro-intestinal cancer for all the three models: a dominant model, CG + GG versus CC, b recessive model, CG + CC versus GG, c homozygous model, GG versus CC

Fig. 3

Figure showing forest plot of stratified analysis based on cancer types i.e. gastro-intestinal (GI) and upper aero-digestive tract (UADT) cancer in association with OGG1 Ser326Cys polymorphism for all the three models: a dominant model, CG + GG versus CC, b recessive model, CG + CC versus GG, c homozygous model, GG versus CC

Fig. 4

Figure showing funnel plot for publication bias a dominant model, CG + GG versus CC, b recessive model, CG + CC versus GG, c homozygous model, GG versus CC