title: The Catechol-O-Methyltransferase Val158Met Polymorphism Contributes to the Risk of Breast Cancer in the Chinese Population: An Updated Meta-Analysis.
abstract: OBJECTIVE
  Catechol-O-methyltransferase (COMT) enzyme plays a central role in estrogen-induced carcinogenesis. Emerging evidence from association studies has revealed that the functional Val158Met polymorphism (rs4680 G>A) of the Catechol-O-methyltransferase gene (COMT) has been implicated in susceptibility to breast cancer in the Chinese population, while results of individual published studies remain inconclusive and inconsistent. To assess this association in the Chinese population, a meta-analysis was performed.
  
  
  METHODS
  Eligible studies were searched on MEDLINE, Embase, Cochrane Library, China National Knowledge Infrastructure, and the Chinese Biomedicine Database. Odds ratios (ORs) with their corresponding 95% confidence intervals (CIs) were pooled to assess the association between COMT polymorphisms and the risk of breast cancer using RevMan 5.2 and Stata 12.0 software.
  
  
  RESULTS
  The meta-analysis included 14 eligible studies, with a total of 4,626 breast cancer cases and 5,637 controls. Overall, the COMT Val158Met polymorphism (rs4680 G>A) was significantly associated with an increased risk of breast cancer in several genetic models (A/A vs. G/G: OR, 1.59, 95% CI, 1.12-2.27; A/A vs. G/A+G/G: OR, 1.62, 95% CI, 1.14-2.29; A vs. G: OR, 1.15, 95% CI, 1.00-1.32), and a subgroup analysis according to menopausal status showed that this association was especially evident among premenopausal Chinese women (A/A vs. G/G: OR, 1.87, 95% CI, 0.99-3.54; A/A vs. G/A+G/G: OR, 1.94, 95% CI, 1.03-3.63).
  
  
  CONCLUSIONS
  The results of this meta-analysis indicated that COMT Val158Met variants contribute to breast cancer susceptibility in the Chinese population, particularly among premenopausal women.
authors.affiliation: Department of Pathology and the Key Laboratories for Xinjiang Endemic and Ethnic Diseases, Shihezi University School of Medicine, Shihezi, China.
authors.forename: Guo-Xing
authors.initials: GX
authors.lastname: Wan
authors.affiliation: Department of Pathology and the Key Laboratories for Xinjiang Endemic and Ethnic Diseases, Shihezi University School of Medicine, Shihezi, China.
authors.forename: Yu-Wen
authors.initials: YW
authors.lastname: Cao
authors.affiliation: Department of Pathology and the Key Laboratories for Xinjiang Endemic and Ethnic Diseases, Shihezi University School of Medicine, Shihezi, China.
authors.forename: Wen-Qin
authors.initials: WQ
authors.lastname: Li
authors.affiliation: Department of Pathology and the Key Laboratories for Xinjiang Endemic and Ethnic Diseases, Shihezi University School of Medicine, Shihezi, China.
authors.forename: Yu-Cong
authors.initials: YC
authors.lastname: Li
authors.affiliation: Department of Pathology and the Key Laboratories for Xinjiang Endemic and Ethnic Diseases, Shihezi University School of Medicine, Shihezi, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Li
keywords: Breast neoplasms; Catechol-O-methyltransferase; Genetic; Meta-analysis; Polymorphism