title: XRCC1 and OGG1 Gene Polymorphisms and Breast Cancer: A Systematic Review of Literature.
abstract: BACKGROUND
  Known polymorphisms of DNA repair genes can be associated with the risk of many types of cancer. There is no consensus regarding association between XRCC1 and OGG1 with breast cancer (BC).
  
  
  OBJECTIVE
  The aim of this study is to collect relevant published studies systematically.
  
  
  METHODS
  Sixty-two publications were identified through searching PubMed, PubMed Central, ISI web of knowledge, and reference list of related articles.
  
  
  METHODS
  We performed a systematic review according MOOSE guideline criteria. All longitudinal cohort and case-control studies investigating association of any type and grade of breast cancer with XRCC1 and OGG1 gene and their polymorphisms were eligible for initial inclusion.
  
  
  METHODS
  Two authors screened titles and abstracts and extracted all needed information from eligible studies. Four research methodological components causing bias for the association between gene polymorphisms and breast cancer risk, including source of controls sampling, population ethnicity, sample size of studies and menopausal status of cases and controls was used for assessment of quality of studies.
  
  
  RESULTS
  A total of 14,793 breast cancer cases and 15,409 controls were included in assessment of XRCC1 Arg194Trp. Four studies showed significant association and one study showed protective effect of XRCC1 Arg194Trp and BC. A total of 7,716 cases and 7,370 controls were included for XRCC1 Arg280His. Only one study showed significant association of XRCC1 Arg280His and breast cancer (OR = 1.82 (1.06 - 3.15). A total of 27,167 cases and 31,998 controls were included to estimate association between XRCC1 Arg399Gln polymorphism and breast cancer. Seven studies showed significant association and one showed protective effect of XRCC1 Arg399Gln and BC. A total of 9,417 cases and 11,087 controls were included for OGG1 Ser326Cys. Among studies focused on OGG1 Ser326Cys, none showed significant association with breast cancer.
  
  
  CONCLUSIONS
  Systematic search of major databases identify many studies addressing the relationship between BC and susceptible alleles in the base excision repair genes and the fact that there are many variations in the magnitude of association depending on inheritance model and the population of the study.
authors.affiliation: School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors.forename: Ali
authors.initials: A
authors.lastname: Sanjari Moghaddam
authors.affiliation: Iranian Research Center on Healthy Aging, Sabzevar University of Medical Sciences, Sabzevar, IR Iran.
authors.forename: Milad
authors.initials: M
authors.lastname: Nazarzadeh
authors.affiliation: Department of Medical Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors.forename: Rezvan
authors.initials: R
authors.lastname: Noroozi
authors.affiliation: Department of Medical Genetics, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Darvish
authors.affiliation: School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran; Iranian Research Center on Healthy Aging, Sabzevar University of Medical Sciences, Sabzevar, IR Iran; Faculty of Health Sciences, Simon Fraser University, BC., Canada.
authors.forename: Alireza
authors.initials: A
authors.lastname: Mosavi Jarrahi
keywords: Breast Neoplasms; OGG1; Polymorphisms; XRCC1