title: [Association between genetic polymorphism in DNA repair genes XRCC3 and risks of laryngeal and hypopharyngeal carcinomas].
abstract: OBJECTIVE
  To study the association between polymorphism of DNA repair gene XRCC3 Thr 241 Met and the risks of developing laryngeal and hypopharyngeal carcinomas.
  
  
  METHODS
  One hundred and seventy five patients with laryngeal or hypopharyngeal carcinoma and 525 cancer-free controls were genotyped for the polymorphism by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using unconditional logistic regression model.
  
  
  RESULTS
  The XRCC3 241 Met allele increased the risk of developing laryngeal carcinoma and hypopharyngeal carcinoma. Comparing with subjects having the XRCC3 241 Thr/Thr genotype, the subjects at least having one XRCC3 241 Met allele had OR of 2. 26 (95% CI 1.33 -3.82). Respectively analyzing the risks of laryngeal carcinoma and hypopharyngeal carcinoma, The allele XRCC3 241 Met increased the risks of developing both laryngeal and hypopharyngeal carcinoma. Comparing with the subjects having the XRCC3 241 Thr/Thr genotype, the subjects with laryngeal carcinoma at least having one XRCC3 241 Met genotype had OR of 2.27 (95% CI 1.26 - 4.09); the subjects with hypopharyngeal carcinoma at least having one XRCC3 241 Met genotype had OR of 2. 99 (95% CI 1.27 - 7.04). Smoking may increase the risk of developing laryngeal carcinoma and hypopharyngeal carcinoma. The interaction of smoking and XRCC3 Thr241 Met increased risk of laryngeal carcinoma and hypopharyngeal carcinoma in a super-multiplicative manner. The subjects with heavy smoking and at least having one XRCC3 241Met allele had OR of 19.09 (95% CI 7.38 -49.40) comparing with those having the XRCC3 241 Thr/ Thr genotype and no smoking, which was greater than the multiplication of ORs both of subjects at least having one 241 Met allele meanwhile without smoking (OR, 0.91; 95% CI, 0.20 - 4.21) and of subjects having XRCC3 241 Thr/Thr genotype meanwhile with smoking (OR, 4.13; 95% CI, 2.38 - 7.17).
  
  
  CONCLUSIONS
  XRCC3 Thr 241 Met plays an important role in the development of laryngeal and hypopharyngeal carcinoma.
authors.affiliation: Department of Otorhinolaryngology Head and Neck Surgery, First Hospital, Shanxi Medical University, Taiyuan 030001, China.
authors.forename: Shu-Xin
authors.initials: SX
authors.lastname: Wen
authors.forename: Xue-Mei
authors.initials: XM
authors.lastname: Zhang
authors.forename: Ping-Zhang
authors.initials: PZ
authors.lastname: Tang
authors.forename: Dan
authors.initials: D
authors.lastname: Zhao
authors.forename: Yong-Li
authors.initials: YL
authors.lastname: Guo
authors.forename: Wen
authors.initials: W
authors.lastname: Tan
authors.forename: Dong-Xin
authors.initials: DX
authors.lastname: Lin
mesh_terms: D002277:Carcinoma / Q000209:etiology / Q000235:genetics*; D002294:Carcinoma, Squamous Cell; D016022:Case-Control Studies; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006258:Head and Neck Neoplasms / Q000209:etiology / Q000235:genetics*; D006801:Humans; D007012:Hypopharyngeal Neoplasms / Q000209:etiology / Q000235:genetics*; D007822:Laryngeal Neoplasms / Q000209:etiology / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D018307:Neoplasms, Squamous Cell / Q000209:etiology / Q000235:genetics*; D011110:Polymorphism, Genetic; D012307:Risk Factors; D012907:Smoking; D000077195:Squamous Cell Carcinoma of Head and Neck
chemical_list: D004268:DNA-Binding Proteins; C110901:X-ray repair cross complementing protein 3