title: Genetic Association of XRCC1 Gene rs1799782, rs25487 and rs25489 Polymorphisms with Risk of Thyroid Cancer: a Systematic Review and Meta-Analysis
abstract: Background: A number of case-control studies have evaluated associations between the X-ray cross complementary
  group 1 protein (XRCC1) gene rs1799782 (Arg194Trp), rs25487 (Arg399Gln) and rs25489 (Arg280His) polymorphisms
  and thyroid cancer (TC) risk, but the results remain inconclusive. Materials and Methods: A systematic literature search
  was performed using PubMed and Google Scholar Search. According to defined criteria data were extracted and pooled
  odds ratios with 95% confidence intervals were calculated under five genetic models. Results: A total of 8 studies with
  1,672 cases and 2,805 controls for the rs1799782 polymorphism, 14 studies with 2,506 cases and 5,180 controls for the
  rs25487 polymorphism, and 11 studies with 2,197 cases and 4,761 controls for the rs25489 polymorphism were included
  in this meta-analysis. Overall, there was a statistical association between XRCC1 rs1799782 polymorphism and TC
  risk with the homozygote genetic model (TT vs. CC: OR = 1.815, 95% CI = 1.115-2.953, p= 0.016) and the recessive
  genetic model (TT vs. TC+CC: OR = 1.854, 95% CI = 1.433-2.399, p= <0.001). In the subgroup analysis by ethnicity,
  significantly increased TC risk was observed only in Asians under the recessive model (TT vs. TC+CC: OR = 1.816,
  95% CI = 1.398-2.358, p= <0.001). In addition, there was no positive association between XRCC1 rs25487 and rs25489
  polymorphisms and risk of TC. However, there was a significant association between XRCC1 rs25487 polymorphism
  risk of TC among Caucasians with allele genetic comparison (A vs. G: OR= 0.882, 95% CI = 0.794-0.979, p= 0.136)
  and dominant genetic comparison (AA+AG vs. GG: OR=0.838, 95% CI = 0.728-0.965, p= 0.014). Conclusions: The
  results of our meta-analysis suggest an increased risk of TC with the XRCC1 rs1799782 and rs25487 polymorphisms.
  However, the XRCC1 rs25489 polymorphism appeared to be without influence.
authors.affiliation: Department of General Surgery, Shahid Sadoughi University of Medical Sciences, Yazd, Iran. Email: mohammad.foratyazdi@gmail.com
authors.forename: Jamal
authors.initials: J
authors.lastname: Jafari Nedooshan
authors.forename: Mohammad
authors.initials: M
authors.lastname: Forat Yazdi
authors.forename: Hossein
authors.initials: H
authors.lastname: Neamatzadeh
authors.forename: Masoud
authors.initials: M
authors.lastname: Zare Shehneh
authors.forename: Saeed
authors.initials: S
authors.lastname: Kargar
authors.forename: Niloofar
authors.initials: N
authors.lastname: Seddighi
keywords: Thyroid cancer; XRCC1 gene; polymorphism; association; meta-analysis