title: MTHFR gene A1298C polymorphisms are associated with breast cancer risk among Chinese population: evidence based on an updated cumulative meta-analysis.
abstract: OBJECTIVE
  Published studies on the association between methylenetetrahydrofolate reductase (MTHFR) gene A1298C polymorphisms and breast cancer risk among Chinese population have yielded conflicting results. The purpose of this study was to clarify the association between MTHFR gene A1298C polymorphisms and breast cancer risk among Chinese population.
  
  
  METHODS
  Systematic searches were performed through the database of Medline/PubMed, Science Direct, Elsevier, CNKI and Wanfang Medical Online.
  
  
  RESULTS
  Overall, a significantly increased risk of breast cancer was observed among the subjects carrying MTHFR gene A1298C AC+CC genotype (odds ratio [OR]=1.05 with 95% confidence interval [CI]: 1.01-1.10) as compared to those carrying AA genotype among total Chinese population. We did not observe any significant association between MTHFR gene A1298C polymorphisms and the risk of breast cancer under the additional genetic models of AC vs. AA, CC vs. AA and C-allele vs. A-allele (OR=1.00 with 95% CI: 0.97-1.02, OR=1.01 with 95% CI: 1.00-1.02 and OR=1.00 with 95% CI: 0.99-1.02, respectively). The cumulative meta-analysis showed similar results. In subgroup analysis, we observed subjects carrying AC+CC genotype had an increased breast cancer risk compared with those carrying AA genotype among the studies of sample size less than 1000. We did not observe any significant association between MTHFR gene A1298C polymorphisms and breast cancer risk in additional subgroup analyses.
  
  
  CONCLUSIONS
  Our results suggest that MTHFR gene A1298C AC+CC genotype may be a risk factor for the development of breast cancer among Chinese population. Well-designed studies with a large sample size are needed to further confirm our findings.
authors.affiliation: Department of Toxicology, Henan Center for Disease Control and PreventionZhengzhou 450016, China; Henan Collaborative Innovation Center of Molecular Diagnosis and Laboratory Medicine, Xinxiang Medical UniversityXinxiang 453003, China.
authors.forename: Yadong
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Epidemiology, School of Public Health, Zhengzhou University Zhengzhou 450001, China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Yang
authors.affiliation: Henan Collaborative Innovation Center of Molecular Diagnosis and Laboratory Medicine, Xinxiang Medical University Xinxiang 453003, China.
authors.forename: Guangcai
authors.initials: G
authors.lastname: Duan
keywords: Chinese; MTHFR; breast cancer; polymorphism; risk