title: Prognostic role of microRNA-21 in gastric cancer: a meta-analysis.
abstract: BACKGROUND
  Mounting evidence shows that microRNAs may be useful as prognostic biomarkers of gastric cancer. The aim of this meta-analysis was to summarize the predictive role of miR-21 for survival in patients with gastric cancer and to verify the association between expression of miR-21 and clinical characteristics.
  
  
  METHODS
  All the eligible studies were searched by PubMed and EMBASE and clinical characteristics and survival results were extracted. Then a meta-analysis was carried out to clarify the prognostic role of the miR-21 expression in different subgroups.
  
  
  RESULTS
  We included 8 studies dealing with gastric cancer in this meta-analysis. For overall survival, the pooled hazard ratio of higher miR-21 expression in tumor tissue was 2.00 (95% CI: 1.39-2.88, P<0.01), which could significantly predict poorer survival in gastric cancer patients. Importantly, subgroup analysis suggested that higher expression of miR-21 correlated with tumor differentiation 0.42 (95% CI: 0.25-0.70 p<0.01), lymph node metastasis 6.39(95% CI: 3.11-13.14, P<0.01), and TNM stage 0.38 (95% CI: 0.21-0.67, P<0.01).
  
  
  CONCLUSIONS
  This meta-analysis indicates that miR-21 detection has a prognostic value in patients with gastric cancer. In addition, overexpression of miR-21 is associated with worse tumor differentiation, lymph node metastasis, and TNM stage.
authors.affiliation: Department of Surgery, Shanghai Institute of Digestive Surgery, Shanghai Key Laboratory of Gastric Neoplasms, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China (mainland).
authors.forename: Zhenqiang
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Surgery, Shanghai Institute of Digestive Surgery, Shanghai Key Laboratory of Gastric Neoplasms, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China (mainland).
authors.forename: Qiang
authors.initials: Q
authors.lastname: Cai
authors.affiliation: Department of Surgery, Shanghai Institute of Digestive Surgery, Shanghai Key Laboratory of Gastric Neoplasms, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China (mainland).
authors.forename: Zhaoyan
authors.initials: Z
authors.lastname: Jiang
authors.affiliation: Department of Surgery, Shanghai Institute of Digestive Surgery, Shanghai Key Laboratory of Gastric Neoplasms, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China (mainland).
authors.forename: Bingya
authors.initials: B
authors.lastname: Liu
authors.affiliation: Department of Surgery, Shanghai Institute of Digestive Surgery, Shanghai Key Laboratory of Gastric Neoplasms, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China (mainland).
authors.forename: Zhenggang
authors.initials: Z
authors.lastname: Zhu
authors.affiliation: Department of Surgery, Shanghai Institute of Digestive Surgery, Shanghai Key Laboratory of Gastric Neoplasms, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China (mainland).
authors.forename: Chen
authors.initials: C
authors.lastname: Li
mesh_terms: D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism*; D011379:Prognosis; D017594:Publication Bias; D013274:Stomach Neoplasms / Q000175:diagnosis* / Q000235:genetics*; D016019:Survival Analysis
chemical_list: C524940:MIRN21 microRNA, human; D035683:MicroRNAs