title: Prognostic role of microRNA-21 in colorectal cancer: a meta-analysis.
abstract: BACKGROUND
  To date, many studies have shown that microRNAs (miRNA) exhibit altered expression in various cancers and may play an important role as prognostic biomarker of cancers. The present meta-analysis summarizes the recent advances in the use of microRNA-21 (miR-21) in the assessment of colorectal cancer and analyzes the prognostic role of miR-21 for survival outcome.
  
  
  RESULTS
  The present meta-analysis was performed by searching PubMed through multiple search strategies. Data were extracted from studies comparing overall survival (OS) in patients with colorectal cancer who showed higher expression of miR-21 than similar patients. Pooled hazard ratios (HRs) of miR-21 for survival and 95% confidence intervals (CI) were calculated. Seven studies with a total of 1174 patients were included this meta-analysis. For overall survival (OS), the pooled hazard ratio (HR) of higher miR-21 expression in colorectal cancer was 1.76 (95% CI: 1.34-2.32, P=0.000). After elimination of heterogeneity, the pooled HR was 2.32 (95% CI: 1.82-2.97, P=0.000), which was found to significantly predict poorer survival. The subgroup analysis suggested that elevated miR-21 level and patients' survival correlated with III/IV stage (HR=5.35, 95% CI: 3.73-7.66).
  
  
  CONCLUSIONS
  The present findings suggest that high expression of miR-21 might predict poor prognosis in patients with colorectal cancer.
authors.affiliation: Department of Radiation Oncology, Nantong Tumor Hospital, Nantong, Jiangsu, China.
authors.forename: Xiaochun
authors.initials: X
authors.lastname: Xia
authors.forename: Baixia
authors.initials: B
authors.lastname: Yang
authors.forename: Xiaogang
authors.initials: X
authors.lastname: Zhai
authors.forename: Xiangyang
authors.initials: X
authors.lastname: Liu
authors.forename: Kang
authors.initials: K
authors.lastname: Shen
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Wu
authors.forename: Jing
authors.initials: J
authors.lastname: Cai
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000401:mortality* / Q000473:pathology; D005260:Female; D015870:Gene Expression; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D009367:Neoplasm Staging; D011379:Prognosis; D016016:Proportional Hazards Models
chemical_list: D014408:Biomarkers, Tumor; C524940:MIRN21 microRNA, human; D035683:MicroRNAs