title: Association of 677 C>T (rs1801133) and 1298 A>C (rs1801131) polymorphisms in the MTHFR gene and breast cancer susceptibility: a meta-analysis based on 57 individual studies.
abstract: OBJECTIVE
  The 677 C>T and 1298 A>C polymorphisms of methylenetetrahydrofolate reductase (MTHFR) gene have been widely reported and considered to have a significant effect on breast cancer risk, but the results are inconsistent. A meta-analysis based on 57 eligible studies was carried out to clarify the role of MTHFR gene polymorphisms in breast cancer.
  
  
  RESULTS
  Eligible articles were identified by searching databases including PubMed, Web of Science, EMBASE, CNKI and CBM for the period up to August 2012. Finally, a total of 57 studies were included in this meta-analysis. Crude ORs with 95% CIs were used to assess the association between the MTHFR polymorphisms and breast cancer risk. The pooled ORs were performed with additive model, dominant model and recessive model, respectively. Subgroup analysis was also performed by ethnicity. The statistical heterogeneity across studies was examined with χ2-based Q-test. A meta-analysis was performed using the Stata 12.0 software. Overall, the 677 C allele was significantly associated with breast cancer risk (OR = 0.942, 95%CI = 0.898 to 0.988) when compared with the 677 T allele in the additive model, and the same results were also revealed under other genetic models. Simultaneously, the 1298 A allele was not associated with the breast cancer susceptibility when compared with the 1298 C allele (OR = 0.993, 95%CI = 0.978 to 1.009). Furthermore, analyses under the dominant, recessive and the allele contrast model yielded similar results.
  
  
  CONCLUSIONS
  The results of this meta-analysis suggest that 677 C>T polymorphism in the MTHFR gene may contribute to breast cancer development. However, the 1298 A>C polymorphism is not significantly associated with increased risks of breast cancer.
authors.affiliation: Department of Oncology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, P. R. China.
authors.forename: Kai
authors.initials: K
authors.lastname: Li
authors.affiliation: Department of Oncology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, P. R. China.
authors.forename: Wusheng
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Oncology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, P. R. China.
authors.forename: Xi
authors.initials: X
authors.lastname: Dong
mesh_terms: D000483:Alleles; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D005260:Female; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D012307:Risk Factors
chemical_list: C573423:MTHFR protein, human; D042965:Methylenetetrahydrofolate Reductase (NADPH2)