Background: The antioxidant enzyme glutathione peroxidase 3 (GPX3) can lessen the oxidative stress in the thyroid gland. We tested for the association between tagging single nucleotide polymorphisms (tSNPs) of the GPX3 gene and the risk of differentiated thyroid cancer (DTC).
Methods: A total of 6 tSNPs (rs3763013, rs8177412, rs3805435, rs3828599, rs3792796, and rs2070593) of GPX3 were genotyped in Chinese DTC cases (n = 268) and controls (n = 378). Multivariate logistic regression was performed to estimate the genetic effect with adjustment for age and sex.
Results: There was no significant finding of genotype analysis in each tSNP associated with DTC, papillary thyroid carcinoma, or patients with regional lymph node metastasis. In the older group (age > or =45 years), subjects who carried at least 1 G allele of rs3805435 had a decreased risk of DTC compared with patients of AA homozygote (sex- and age-adjusted odds ratio [OR] = 0.50, P = .009). An individual with at least 1 T allele of rs3828599 had a decreased risk of DTC compared with an individual of the CC homozygote (sex- and age-adjusted OR = 0.53, P = .018). An individual carrying the TC genotype of rs8177412 in the older group had an increased risk of DTC than controls (sex- and age-adjusted OR = 1.73, P = .037).
Conclusion: We found that the G allele of rs3805435 or the T allele of rs3828599 may exert a protective effect for DTC in the older population, whereas the C allele of rs8177412 confers an increased risk effect for DTC.