Therefore, the possible association of the hOGG1Ser326Cys gene variant with insulin sensitivity was investigated in 279 normal glucose-tolerant subjects without history of cancer.
This study supported the first study by Sugimura et al (Cancer Epidemiol Biomarkers Prev, 1999; 8: 669-674), that the association of OGG1Ser326Cys polymorphism was limited for the risk of lung adenocarcinoma.
We found that the hOGG1Ser326Cys polymorphism was significantly associated with overall cancer risk (Cys/Cys vs. Ser/Ser: OR = 1.19, 95%CI = 1.09-1.30, P<0.001; Cys/Cys vs. Cys/Ser+Ser/Ser: OR = 1.16, 95%CI = 1.08-1.26, P<0.001).
This study suggests that the OGG1 polymorphism is not associated with the risk of development of CRC in the Kashmiri population in general but modulates the risk of cancer development in colon via interaction with many dietary factors.
Given the crucial role of the APEX and OGG1 proteins in BER of oxidative DNA damage, the identified polymorphisms are good candidates for genetic epidemiologic studies of cancer susceptibility, while the finding that three of 20 (15%) endometrial tumors have somatic mutations in APEX suggests that inactivation of the BER pathway is important for the development of endometrial cancer in at least a subset of cases.
Urinary excretion of 8-oxodG, genotype and expression of OGG1 have been associated with risk of cancer in cohort settings, whereas altered levels of damage, repair or urinary excretion in case-control settings may be a consequence rather than the cause of the disease.
The CRC risk was higher in patients with the OGG1326Ser/Cys + Cys/Cys genotype (OR = 1.38, 95%CI: 1.03-1.85, P = 0.030), particularly high in patients with stage III + IV cancer (OR = 1.48, 95%CI: 1.03-2.13) compared with patients with the Ser/Ser genotype.
The authors conducted meta-analyses of associations between genes in the base excision repair pathway and cancer risk, focusing on three key genes: 8-oxoguanine DNA glycosylase (OGG1), apurinic/apyrimidinic endonuclease (APE1/APEX1), and x-ray repair cross-complementing group 1 (XRCC1).
Association between OGG1Ser326Cys, XPC Lys939Gln, XPD Lys751Gln polymorphisms and the susceptibility tho cancer and the oxidative stress status were evaluated.
Overall, significant association was observed between OGG1Ser326Cys polymorphism and cancer risk in all genetic models except for heterozygote model (Cys/Cys + Cys/Ser vs Ser/Ser: OR 1.071, 95 % CI 1.019-1.125; Cys/Cys vs Cys/Ser + Ser/Ser: OR 1.159, 95 % CI 1.076-1.248; Cys/Cys vs Ser/Ser: OR 1.202, 95 % CI 1.105-1.308).
Our aim in this review is to compile published studies, including some controversial results on the association between the OGG1Ser326Cys polymorphism and the risk of cancer.
For UADT cancer risk, associations were observed for the homozygous carriers of the variant alleles of MGMT L84F [odds ratio (OR) 2.35, 95% confidence interval (CI) 1.32-4.20], MGMT 171C > T (OR 2.24, 95% CI 1.20-4.17) and OGG1S326C (OR 2.07, 95% CI 1.15-3.73) whilst three variants were associated with a protective effect (XPA 23G > A, P for trend 0.022, APEX Q51H, P for trend 0.036, CHEK2 intron 9-200T > C, P for trend 0.009).
A frequent polymorphism in the human OGG1 gene, rs1052133, causes the substitution of serine by cysteine at amino acid 326 of the protein and has been associated with an altered risk for various types of cancer in some populations.
In studies that explored potential interactions with environmental factors, cancer risk for hOGG1 genotypes differed depending on exposure, especially for colon cancer.