title: Prognostic role of the let-7 family in various carcinomas: A meta-analysis update.
abstract: OBJECTIVE
  The role of let-7 family members in cancer prognosis has been the subject of increasing interest; however, the correlation between let-7 expression and cancer prognosis remains unknown. The goal of this study was to investigate the prognostic role of let-7 expression by performing a meta-analysis update of 31 studies.
  
  
  METHODS
  All relevant studies were searched on PubMed and Web of Science. The pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated, and subgroup analysis was performed for overall survival (OS) and disease-free survival (DFS) to evaluate the relationship between high let-7 expression and cancer prognosis. Heterogeneity and publication bias were also investigated.
  
  
  RESULTS
  We discovered that high let-7 expression can predict a better OS (pooled HR=0.69, 95% CI 0.60-0.80, transformed from lnHR and its 95% CI) and DFS (pooled HR=0.72, 95% CI 0.54-0.96, transformed from lnHR and its 95% CI) in various carcinomas, especially in digestive cancer. Subgroup analysis showed that high let-7 expression was significantly associated with a better DFS in Asians (pooled HR=0.50, 95% CI 0.39-0.64, transformed from lnHR and its 95% CI).
  
  
  CONCLUSIONS
  This meta-analysis showed that high let-7 expression is a prognostic factor for better OS and DFS in cancer patients, with particularly better DFS among the Asian populations. These results suggest that clinicians should treat patients with low let-7 expression more carefully. Future studies in large-scale populations among different ethnicities and regions are needed to definitively determine if let-7 expression can be used as a predicative biomarker for clinical assessment.
authors.affiliation: Department of Medical Oncology, The First Hospital, China Medical University, Shenyang, Liaoning Province, China.
authors.forename: Chen-Lu
authors.initials: CL
authors.lastname: Zhang
authors.forename: Zhi
authors.initials: Z
authors.lastname: Li
authors.forename: Yun-Peng
authors.initials: YP
authors.lastname: Liu
authors.forename: Ying
authors.initials: Y
authors.lastname: Wu
authors.forename: Xiu-Juan
authors.initials: XJ
authors.lastname: Qu
mesh_terms: D018572:Disease-Free Survival; D006801:Humans; D035683:MicroRNAs / Q000502:physiology*; D009369:Neoplasms / Q000235:genetics* / Q000401:mortality; D011379:Prognosis; D017594:Publication Bias
chemical_list: D035683:MicroRNAs; C487931:mirnlet7 microRNA, human