title: XRCC1 Arg194Trp and Arg399Gln polymorphisms and risk of extrahepatic cholangiocarcinoma: a hospital-based case-control study in China.
abstract: BACKGROUND
  Extrahepatic cholangiocarcinoma (ECCA) is a rare but devastating malignancy. Up to 90% of patients presenting with ECCA have no identifiable risk factors. The base excision repair (BER) pathway has a principal role in the repair of mutations caused by oxidized or reduced bases. The XRCC1 is one of the key proteins in the BER pathway. In this study, we investigated the influence of XRCC1 Arg194Trp and Arg399Gln polymorphisms on ECCA incidence.
  
  
  METHODS
  The study included 189 ECCA patients and 216 controls. Genotypes were detected by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) method.
  
  
  RESULTS
  For codon 194, the genotype frequencies of C/C, T/C and T/T were 51.3, 43.4 and 5.3%, respectively, in the ECCA cases compared with 54.2, 38.9 and 6.9%, respectively, in the controls. No statistically significant differences were observed in the genotype frequencies of codon 194 between the two groups compared to the control (TC, OR: 0.85, 95% CI: 0.57-1.28, TT, OR: 1.24, 95% CI: 0.54-2.89, TC+TT, OR: 0.89, 95% CI: 0.60-1.32). For codon 399, the genotype frequencies of G/G, G/A and A/A were 54.0, 37.0 and 9.0%, respectively, in the ECCA cases compared with 56.1, 39.8 and 4.1%, respectively, in the controls. No statistically significant differences were observed in the genotype frequencies codon 399 between the two groups compared to the control (GA, OR: 1.04, 95% CI: 0.69-1.56, AA, OR: 0.45, 95% CI: 0.19-1.04, GA+AA, OR: 0.92, 95% CI: 0.62-1.36). Meanwhile, no statistically significant differences were found in the haplotype and risk of developing ECCA compared to the control (CA, OR: 0.83, 95% CI: 0.49-1.39, TG, OR: 0.96, 95% CI: 0.58-1.60, TA, OR: 0.83, 95% CI: 0.38-1.82).
  
  
  CONCLUSIONS
  The present study suggested that Arg194Trp and Arg399Gln polymorphism in the DNA repair gene XRCC1 was not statistically associated with risk of ECCA. It would be necessary to confirm these findings in a large sample size and multiethnic population study in future.
authors.affiliation: Department of Hepatobiliary Surgery, Afﬁliated Cancer Hospital of Guangzhou Medical University 78 Hengzhigang Road, Guangzhou 510095, China.
authors.forename: Yuanfeng
authors.initials: Y
authors.lastname: Gong
authors.affiliation: Department of Breast and Thyroid Surgery, Shandong Provincial Hospital Affiliated to Shandong University 324 Jingwu-Weiqi Road, Jinan 250021, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Qi
authors.affiliation: Department of Hepatobiliary Surgery, Afﬁliated Cancer Hospital of Guangzhou Medical University 78 Hengzhigang Road, Guangzhou 510095, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Hepatobiliary Surgery, Afﬁliated Cancer Hospital of Guangzhou Medical University 78 Hengzhigang Road, Guangzhou 510095, China.
authors.forename: Runya
authors.initials: R
authors.lastname: Fang
authors.affiliation: Department of Hepatobiliary Surgery, Afﬁliated Cancer Hospital of Guangzhou Medical University 78 Hengzhigang Road, Guangzhou 510095, China.
authors.forename: Cong
authors.initials: C
authors.lastname: Mai
authors.affiliation: Department of Hepatobiliary Surgery, Afﬁliated Cancer Hospital of Guangzhou Medical University 78 Hengzhigang Road, Guangzhou 510095, China.
authors.forename: Tiejun
authors.initials: T
authors.lastname: Chen
authors.affiliation: Department of Hepatobiliary Surgery, Afﬁliated Cancer Hospital of Guangzhou Medical University 78 Hengzhigang Road, Guangzhou 510095, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Tang
authors.affiliation: Department of Hepatobiliary Surgery, Afﬁliated Cancer Hospital of Guangzhou Medical University 78 Hengzhigang Road, Guangzhou 510095, China.
authors.forename: Yunqiang
authors.initials: Y
authors.lastname: Tang
keywords: XRCC1; cholangiocarcinoma; polymorphism; risk; susceptibility