title: Association of COMT Val158Met polymorphism and breast cancer risk: an updated meta-analysis.
abstract: BACKGROUND
  Catechol-O-methyltransferase (COMT) is one of the most important enzymes involved in estrogen metabolism and its functional genetic polymorphisms may be associated with breast cancer (BC) risk. Many epidemiological studies have been conducted to explore the association between the COMT Val158Met polymorphism and breast cancer risk. However, the results remain inconclusive. In order to derive a more precise estimation of this relationship, a large meta-analysis was performed in this study.
  
  
  METHODS
  Systematic searches of the PubMed, Embase and Cochrane Library were performed. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the strength of the association.
  
  
  RESULTS
  A total of 56 studies including 34,358 breast cancer cases and 45,429 controls were included. Overall, no significant associations between the COMT Val158Met polymorphism and breast cancer risk were found for LL versus HH, HL versus HH, LL versus HL, recessive model LL versus HL+HH, and dominant model LL+HL versus HH. In subgroup analysis by ethnicity, source of controls, and menopausal status, there was still no significant association detected in any of the genetic models.
  
  
  CONCLUSIONS
  Our meta-analysis results suggest that the COMT Val158Met polymorphism may not contribute to breast cancer susceptibility.
  The virtual slides(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs4806123577708417.
authors.affiliation: Department of Clinical Laboratory, First Affiliated Hospital of Guangxi Medical University, Nanning 530021, Guangxi, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Qin
authors.forename: Qiliu
authors.initials: Q
authors.lastname: Peng
authors.forename: Aiping
authors.initials: A
authors.lastname: Qin
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Chen
authors.forename: Liwen
authors.initials: L
authors.lastname: Lin
authors.forename: Yan
authors.initials: Y
authors.lastname: Deng
authors.forename: Li
authors.initials: L
authors.lastname: Xie
authors.forename: Juanjuan
authors.initials: J
authors.lastname: Xu
authors.forename: Haiwei
authors.initials: H
authors.lastname: Li
authors.forename: Taijie
authors.initials: T
authors.lastname: Li
authors.forename: Shan
authors.initials: S
authors.lastname: Li
authors.forename: Jinmin
authors.initials: J
authors.lastname: Zhao
mesh_terms: D001943:Breast Neoplasms / Q000201:enzymology / Q000208:ethnology / Q000235:genetics* / Q000473:pathology; D016022:Case-Control Studies; D002394:Catechol O-Methyltransferase / Q000235:genetics*; D016009:Chi-Square Distribution; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D016017:Odds Ratio; D010641:Phenotype; D011110:Polymorphism, Genetic; D018570:Risk Assessment; D012307:Risk Factors
chemical_list: D002394:Catechol O-Methyltransferase