title: Lack of Association between an XRCC1 Gene Polymorphism and Colorectal Cancer Survival in Thailand.
abstract: BACKGROUND
  Colorectal cancer (CRC) is one of the most common causes of death worldwide and in Thailand. The X-ray repair cross-complementary protein 1 (XRCC1) is required for efficient DNA repair. The effects of this gene on survival in colorectal cancer remain controversial and have not been reported in Thailand. The aim of this study was to investigate the association of the XRCC1 gene with survival of colorectal cancer patients in a Thai population.
  
  
  METHODS
  Data and blood samples were collected from 255 newly diagnosed and pathologically confirmed CRC patients who were recruited during the period 2002 to 2006 and whose vital status was followed up until 31 October, 2014. Real-time PCR-HRM was used for genotype identification. The Kaplan-Meier method, the log-rank test, and Cox proportional hazard regression were used to estimate cumulative survival curves and compare various survival distributions and adjusted hazard ratios.
  
  
  RESULTS
  Most of the cases were males, and the median age was 55 years. The median survival time was 2.43 years. The cumulative 1-, 3-, 5-, 7-, and 10 year survival rates were 76.70%, 39.25%, 26.50%, 16.60% and 3.56%, respectively. After adjustment, female gender, ages 50-59 and ≥ 60 years, tumour stage III+IV, a signet-ring cell carcinoma, and poor differentiation had significant associations with increased risk of CRC death. While the XRCC1 Arg/Arg homozygote appeared to be a risk factor for CRC death, the association was not significant.
  
  
  CONCLUSIONS
  The genetic variant in the XRCC1 may not be associated with the survival of CRC patients in Thailand. Further studies are needed to verify our findings.
authors.affiliation: Epidemiology and Biostatistics Section, Faculty of Public Health, Khon Kaen University, Khon Kaen E-mail : supannee@kku.ac.th.
authors.forename: Pallop
authors.initials: P
authors.lastname: Siewchaisakul
authors.forename: Krittika
authors.initials: K
authors.lastname: Suwanrungruang
authors.forename: Kirati
authors.initials: K
authors.lastname: Poomphakwaen
authors.forename: Surapon
authors.initials: S
authors.lastname: Wiangnon
authors.forename: Supannee
authors.initials: S
authors.lastname: Promthet
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000453:epidemiology / Q000235:genetics / Q000401:mortality* / Q000473:pathology; D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000235:genetics*; D018279:Carcinoma, Signet Ring Cell / Q000453:epidemiology / Q000235:genetics / Q000401:mortality* / Q000473:pathology; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000235:genetics / Q000401:mortality* / Q000473:pathology; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D005500:Follow-Up Studies; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011379:Prognosis; D060888:Real-Time Polymerase Chain Reaction; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate; D013785:Thailand; D000076105:X-ray Repair Cross Complementing Protein 1
chemical_list: D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; D000076105:X-ray Repair Cross Complementing Protein 1; C000619371:XRCC1 protein, human