Association between the XRCC1 Polymorphisms and Thyroid Cancer Risk: A Meta-Analysis from Case-Control Studies

BACKGROUND The previous published data on the association between the X-ray repair cross-conplementation group 1 (XRCC1) polymorphisms and thyroid cancer risk remained controversial. Hence, we performed a meta-analysis on all available studies that provided 1729 cases and 3774 controls (from 11 studies) for XRCC1 Arg399Gln, 1040 cases and 2487 controls for Arg194Trp (from 7 studies), and 1432 cases and 3356 controls for Arg280His (from 8 studies). METHODOLOGY/PRINCIPAL FINDINGS PubMed, CNKI, and EMBASE database were searched to identify relevant studies. Overall, no significant association was found between XRCC1 Arg399Gln (recessive model: OR = 0.95, 95% CI = 0.77-1.15; dominant model: OR = 0.89, 95% CI = 0.75-1.05; homozygote model: OR = 0.92, 95% CI = 0.69-1.23; Heterozygote model: OR = 0.91, 95% CI = 0.80-1.03; additive model: OR = 0.93, 95% CI = 0.81-1.07), Arg194Trp (recessive model: OR = 1.41, 95% CI = 0.62-3.23; dominant model: OR = 1.01, 95% CI = 0.77-1.34; homozygote model: OR = 1.42, 95% CI = 0.55-3.67; Heterozygote model: OR = 1.03, 95% CI = 0.85-1.26; additive model: OR = 1.08, 95% CI = 0.81-1.42), and Arg280His (recessive model: OR = 1.08, 95% CI = 0.56-2.10; dominant model: OR = 1.01, 95% CI = 0.84-1.22; homozygote model: OR = 1.00, 95% CI = 0.51-1.96; Heterozygote model: OR = 1.04, 95% CI =0.75-1.42; additive model: OR = 1.03, 95% CI = 0.86-1.23) and thyroid cancer risk when all the eligible studies were pooled into the meta-analysis. In the further stratified and sensitivity analyses, significant association was still not found in these three genetic polymorphisms. CONCLUSIONS/SIGNIFICANCE In summary, this meta-analysis indicates that XRCC1 Arg399Gln, Arg280His, and Arg194Trp are not associated with thyroid cancer.