title: Prognostic value of microRNA-21 in pancreatic ductal adenocarcinoma: a meta-analysis.
abstract: BACKGROUND
  Recently, microRNA-21 (miR-21) has been reported to be associated with prognosis of pancreatic ductal adenocarcinoma (PDAC). The present studies aimed to evaluate the prognostic value of miR-21 for PDAC with meta-analysis.
  
  
  METHODS
  A systematic search in the PubMed and other databases was conducted to identify eligible studies. The pooled hazard ratios (HRs) with 95% confidence interval (CI) were calculated. The meta-analysis was conducted using the STATA 12.0 software.
  
  
  RESULTS
  A total of 12 articles (13 studies) which included 963 cases were selected for the meta-analysis. Elevated miR-21 expression was significantly predictive of poor overall survival (HR = 2.05, 95% CI 1.71-2.46, P < 0.001). In the subgroup analyses, similar results were observed in Asian (HR = 2.09, 95% CI 1.62-2.71, P < 0.001) and Caucasian (HR = 2.36, 95% CI 1.53-3.65, P < 0.001); in tissue sample (HR = 2.14, 95% CI 1.73-2.65, P < 0.001) and serum sample (HR = 1.84, 95% CI 1.30-2.60, P = 0.001); with quantitative real-time polymerase chain reaction assay method (HR = 2.31, 95% CI 1.86-2.86, P < 0.001); and in patients receiving adjuvant chemotherapy (HR = 2.37, 95% CI 1.88-3.00, P < 0.001). The association between miR-21 expression level and lymph node metastasis was statistically significant (OR = 1.45, 95% CI 1.02-2.06, P = 0.038). However, no significant relationship between miR-21 expression level and sex or vascular invasion or neural infiltration was observed (P > 0.05).
  
  
  CONCLUSIONS
  Our meta-analysis indicated that elevated miR-21 expression level can predict poor prognosis in patients with PDAC.
authors.affiliation: Department of Gastrointestinal Surgery, Shaoxing People's Hospital, Shaoxing Hospital of Zhejiang University, No. 568, Zhongxing North Road, Shaoxing, 312000, China.
authors.forename: Geng-yuan
authors.initials: GY
authors.lastname: Hu
authors.affiliation: Department of Gastrointestinal Surgery, Shaoxing People's Hospital, Shaoxing Hospital of Zhejiang University, No. 568, Zhongxing North Road, Shaoxing, 312000, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Tao
authors.affiliation: Department of Gastrointestinal Surgery, Shaoxing People's Hospital, Shaoxing Hospital of Zhejiang University, No. 568, Zhongxing North Road, Shaoxing, 312000, China. wangwei_sxph@163.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Gastrointestinal Surgery, Shaoxing People's Hospital, Shaoxing Hospital of Zhejiang University, No. 568, Zhongxing North Road, Shaoxing, 312000, China.
authors.forename: Ke-wei
authors.initials: KW
authors.lastname: Ji
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics*; D021441:Carcinoma, Pancreatic Ductal / Q000175:diagnosis* / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000235:genetics; D011379:Prognosis
chemical_list: D014408:Biomarkers, Tumor; C524940:MIRN21 microRNA, human; D035683:MicroRNAs
keywords: Meta-analysis; MicroRNA-21; Pancreatic ductal adenocarcinoma; Prognosis