title: The association between CDH1 promoter methylation and patients with ovarian cancer: a systematic meta-analysis.
abstract: BACKGROUND
  The down-regulation of E-cadherin gene (CDH1) expression has been regarded as an important event in cancer invasion and metastasis. However, the association between CDH1 promoter methylation and ovarian cancer remains unclear. A meta-analysis was conducted to evaluate the potential role of CDH1 promoter methylation in ovarian cancer.
  
  
  METHODS
  Relevant articles were identified by searches of PubMed, EMBASE, Cochrane Library, CNKI and Wanfang databases. The pooled odds ratio (OR) and corresponding 95 % confidence interval (CI) were calculated to assess the strength of association.
  
  
  RESULTS
  Nine studies were performed using the fixed-effects model in this study, including 485 cancer tissues and 255 nonmalignant tissues. The findings showed that CDH1 promoter methylation had an increased risk of ovarian cancer in cancer tissues (OR = 8.71, P < 0.001) in comparison with nonmalignant tissues. Subgroup analysis of the ethnicity showed that the OR value of CDH1 methylation in Asian population subgroup (OR = 13.20, P < 0.001) was higher than that in Caucasian population subgroup (OR = 3.84, P = 0.005). No significant association was found between ovarian cancer and low malignant potential (LMP) tumor (P = 0.096) among 2 studies, and between CDH1 promoter methylation and tumor stage and tumor histology (all P > 0.05). There was not any evidence of publication bias by Egger's test (all P > 0.05).
  
  
  CONCLUSIONS
  CDH1 promoter methylation can be a potential biomarker in ovarian cancer risk prediction, especially Asians can be more susceptible to CDH1 methylation. However, more studies are still done in the future.
authors.affiliation: Obstetrics and Gynecology Department, The Second Hospital of Jilin University, Changchun, 130041, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Plastic Surgery Department, China-Japan Friendship Hospital Affiliated Jilin University, Changchun, 130033, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Wang
authors.affiliation: Obstetrics and Gynecology Department, The Second People's Hospital of Dunhua, Dunhua, 133700, China.
authors.forename: Yun-Mei
authors.initials: YM
authors.lastname: Zhang
authors.affiliation: Radiology Department, The First Hospital of Jilin University, Changchun, 130041, China. wangwei160118@163.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
mesh_terms: D015703:Antigens, CD; D015820:Cadherins / Q000235:genetics*; D019175:DNA Methylation; D005260:Female; D006801:Humans; D010051:Ovarian Neoplasms / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012307:Risk Factors
chemical_list: D015703:Antigens, CD; C513384:CDH1 protein, human; D015820:Cadherins
keywords: CDH1 promoter; LMP; Methylation; Ovarian cancer