title: Prognostic role of microRNA-181a/b in hematological malignancies: a meta-analysis.
abstract: BACKGROUND
  Emerging evidence has shown that miRNAs participate in human carcinogenesis as tumor suppressors or oncogenes, and have prognostic value for patients with cancers. In recent years, the miR-181 family was found dysregulated in a variety of human cancers and significantly associated with clinical outcome of cancerous patients. MiR-181a and miR-181b (miR-181a/b) were the most investigated members in the family. However, the results of miR-181a/b from different studies were inconsistent. Therefore, we performed a meta-analysis to summarize all the results from available studies, aiming to delineate the prognostic role of miR-181a/b in human cancers.
  
  
  METHODS
  The identified articles were retrieved from the two main on-line databases, PubMed and EMBASE. We extracted and estimated the hazard ratios (HRs) for overall survival (OS), which compared the high and low expression levels of miR-181a/b in patients of the available studies. Each individual HR was used to calculate the pooled HR.
  
  
  RESULTS
  Eleven studies of 1252 patients were selected into the final meta-analysis after a strict filtering and qualifying process. Fixed model or random model method was chosen depending on the heterogeneity between the studies. The subgroup analysis showed that high expressed miR-181a/b could prolong OS in patients with hematological malignancies rather than low expression level (HR = 0.717, P<0.0001). But the expression of miR-181a/b was not significantly relative to OS in patients with various cancers (HR = 0.861, p = 0.356).
  
  
  CONCLUSIONS
  Our study indicates that the expression level of miR-181a/b is significantly associated with OS in hematological malignancies and can be an important clinical prognostic factor for those patients.
authors.affiliation: Department of Hematology, Fujian Medical University Union Hospital, Fuzhou, Fujian Province, China.
authors.forename: Shenglong
authors.initials: S
authors.lastname: Lin
authors.forename: Lili
authors.initials: L
authors.lastname: Pan
authors.forename: Shicheng
authors.initials: S
authors.lastname: Guo
authors.forename: Junjie
authors.initials: J
authors.lastname: Wu
authors.forename: Li
authors.initials: L
authors.lastname: Jin
authors.forename: Jiu-Cun
authors.initials: JC
authors.lastname: Wang
authors.forename: Shaoyuan
authors.initials: S
authors.lastname: Wang
mesh_terms: D019337:Hematologic Neoplasms / Q000235:genetics* / Q000473:pathology*; D006801:Humans; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism*; D011379:Prognosis
chemical_list: C540193:MIrn181 microRNA, human; D035683:MicroRNAs