title: Polymorphisms in genes of nucleotide and base excision repair: risk and prognosis of colorectal cancer.
abstract: OBJECTIVE
  We have undertaken a comprehensive study of common polymorphisms in genes of DNA repair, exploring both the risk of developing colorectal cancer and the prognosis of patients.
  
  
  METHODS
  Subjects from a case-control study (377 cases and 329 controls) designed to assess gene-environment interactions were genotyped by use of an oligonucleotide microarray and the arrayed primer extension technique. Twenty-eight single nucleotide polymorphisms in 15 DNA repair genes were included. The candidate genes belong to different DNA repair pathways: base excision repair (OGG1, LIG3, APEX, POLB, XRCC1, PCNA, and MUTYH), nucleotide excision repair (ERCC1, ERCC2, ERCC4, and ERCC5), double-strand breaks repair (XRCC2, XRCC3, and XRCC9), and reversion repair (MGMT) genes.
  
  
  RESULTS
  Polymorphism OGG1 S326C was associated with an increased risk of colorectal cancer [odds ratio (OR), 2.3; 95% confidence interval (95% CI), 1.1-5.0], the risk being higher in younger individuals. A haplotype of ERCC1 was associated with increased risk (OR, 2.3; 95% CI, 1.0-5.3). POLB P242R was also associated with decreased risk (OR, 0.23; 95% CI, 0.05-0.99), although the number of variant allele carriers was low. In the univariate analysis, adjusted for age, sex, and Dukes' stage, three polymorphisms were significantly associated with better prognosis: XRCC1 R399Q [hazard ratio (HR), 0.38; 95% CI, 0.17-0.85], XRCC3 T141M (HR, 0.66; 95% CI, 0.45-0.97), and MGMT L84F (HR, 0.14; 95% CI, 0.02-0.99). ERCC1 19007T>C was associated with worse prognosis (HR, 1.51; 95% CI, 1.01-2.27). In a multivariate analysis, only XRCC1 R399Q and ERCC1 19007T>C remained significant. These associations were stronger among patients receiving adjuvant chemotherapy.
  
  
  CONCLUSIONS
  Although the overall effect of DNA repair genes in colorectal cancer etiology seems limited, their influence in the response to chemotherapy and prognosis may be more relevant. This knowledge may help to clarify the utility of specific adjuvant treatments according to the individual genetic background.
authors.affiliation: Institut d'Investigació Biomèdica de Bellvitge, Institut Catala d'Oncologia, Hospitalet, Barcelona, Spain.
authors.forename: Victor
authors.initials: V
authors.lastname: Moreno
authors.forename: Federica
authors.initials: F
authors.lastname: Gemignani
authors.forename: Stefano
authors.initials: S
authors.lastname: Landi
authors.forename: Lydie
authors.initials: L
authors.lastname: Gioia-Patricola
authors.forename: Amélie
authors.initials: A
authors.lastname: Chabrier
authors.forename: Ignacio
authors.initials: I
authors.lastname: Blanco
authors.forename: Sara
authors.initials: S
authors.lastname: González
authors.forename: Elisabet
authors.initials: E
authors.lastname: Guino
authors.forename: Gabriel
authors.initials: G
authors.lastname: Capellà
authors.forename: Federico
authors.initials: F
authors.lastname: Canzian
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis / Q000235:genetics* / Q000628:therapy; D000367:Age Factors; D015179:Colorectal Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000628:therapy; D004260:DNA Repair; D005500:Follow-Up Studies; D005838:Genotype; D006801:Humans; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate