title: Promoter Methylation of the Retinoic Acid Receptor Beta2 (RARβ2) Is Associated with Increased Risk of Breast Cancer: A PRISMA Compliant Meta-Analysis.
abstract: BACKGROUND
  Epigenetic studies demonstrate that an association may exist between methylation of the retinoic acid receptor beta2 (RARβ2) gene promoter and breast cancer onset risk, tumor stage, and histological grade, however the results of these studies are not consistent. Hence, we performed this meta-analysis to ascertain a more comprehensive and accurate association.
  
  
  METHODS
  Relevant studies were retrieved from the PubMed, Embase and Chinese National Knowledge Infrastructure databases up to February 28, 2015. After two independent reviewers screened the studies and extracted the necessary data, meta-analysis was performed using Review Manager 5.2 software.
  
  
  RESULTS
  Nineteen eligible articles, including 20 studies, were included in our analysis. Compared to non-cancerous controls, the frequency of RARβ2 methylation was 7.27 times higher in patients with breast cancer (odds ratio (OR) = 7.27, 95% confidence interval (CI) = 3.01-17.52). Compared to late-stage RARβ2 methylated patients, the pooled OR of early-stage ones was 0.81 (OR = 0.81, 95% CI = 0.55-1.17). The OR of low-grade RARβ2 methylated patients was 0.96 (OR = 0.96, 95% CI = 0.74-1.25) compared to high-grade RARβ2 methylated patients.
  
  
  CONCLUSIONS
  RARβ2 methylation is significantly increased in breast cancer samples when compared to non-cancerous controls. RARβ2 could serve as a potential epigenetic marker for breast cancer detection and management.
authors.affiliation: Center for Evidence-Based Medicine and Translational Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Fang
authors.affiliation: Department of General Surgery, Taihe Hospital, Hubei University of Medicine, Shiyan, China.
authors.forename: Zhi-Yuan
authors.initials: ZY
authors.lastname: Jian
authors.affiliation: Department of General Surgery, Taihe Hospital, Hubei University of Medicine, Shiyan, China.
authors.forename: Xian-Feng
authors.initials: XF
authors.lastname: Shen
authors.affiliation: Department of Nursing, Affiliated Hospital of North Sichuan Medical College, Nanchong, 637000, P.R. China.
authors.forename: Xue-Mei
authors.initials: XM
authors.lastname: Wei
authors.affiliation: Center for Evidence-Based Medicine and Translational Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China.
authors.forename: Guo-Zheng
authors.initials: GZ
authors.lastname: Yu
authors.affiliation: Center for Evidence-Based Medicine and Translational Medicine, Zhongnan Hospital of Wuhan University, Wuhan, China.
authors.forename: Xian-Tao
authors.initials: XT
authors.lastname: Zeng
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D019175:DNA Methylation; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D011401:Promoter Regions, Genetic / Q000235:genetics*; D018168:Receptors, Retinoic Acid / Q000235:genetics*
chemical_list: D018168:Receptors, Retinoic Acid; C540966:retinoic acid receptor, beta2, human