title: Prognostic Value of SMAD4 in Pancreatic Cancer: A Meta-Analysis.
abstract: OBJECTIVE
  The prognostic value of SMAD4 in pancreatic cancer has been evaluated in several studies. However, the conclusions remain controversial. Therefore, we aimed to evaluate the association between SMAD4 expression and the outcome of pancreatic cancer patients by performing a meta-analysis.
  
  
  METHODS
  We systematically searched for relevant studies evaluating the relationship between SMAD4 expression and the outcome of pancreatic cancer patients until May 2015. A meta-analysis was performed using STATA 12.0, and pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were used to estimate the strength of the association between SMAD4 expression and the prognosis of pancreatic cancer patients.
  
  
  RESULTS
  The analysis included 1762 patients from 14 studies, with 1401 patients from 11 studies and 927 patients from 8 studies included in the univariate and multivariate analyses, respectively. Loss of SMAD4 expression was found to be significantly correlated with poor overall survival, with the combined HR (95% CI) of 1.20 (1.03-1.40). After adjusting for potential confounders using the Cox regression model, the pooled HR (95% CI) was 1.88 (1.31-2.70). In subgroup analysis, study region, number of patients, follow-up duration, and cutoff value were found to affect the significance of the association between loss of SMAD4 expression and poor prognosis. In addition, there was no evidence of publication bias, as suggested by Begg's and Egger's test.
  
  
  CONCLUSIONS
  Loss of SMAD4 was associated with poor survival and was a negative prognostic indicator in patients with pancreatic cancer.
authors.affiliation: The Key Laboratory of Pathobiology, Ministry of Education, the College of Basic Medical Sciences, Jilin University, Changchun, Jilin 130021, P.R. China.
authors.forename: Xing
authors.initials: X
authors.lastname: Shugang
authors.affiliation: Department of Neurosurgery, The First Clinical Hospital, Jilin University, Changchun, Jilin 130021, P.R. China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Hongfa
authors.affiliation: Department of Neurosurgery, The First Clinical Hospital, Jilin University, Changchun, Jilin 130021, P.R. China.
authors.forename: Liu
authors.initials: L
authors.lastname: Jianpeng
authors.affiliation: Department of Neurosurgery, The First Clinical Hospital, Jilin University, Changchun, Jilin 130021, P.R. China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Xu
authors.affiliation: The Key Laboratory of Pathobiology, Ministry of Education, the College of Basic Medical Sciences, Jilin University, Changchun, Jilin 130021, P.R. China.
authors.forename: Feng
authors.initials: F
authors.lastname: Jingqi
authors.affiliation: The Key Laboratory of Pathobiology, Ministry of Education, the College of Basic Medical Sciences, Jilin University, Changchun, Jilin 130021, P.R. China.
authors.forename: Li
authors.initials: L
authors.lastname: Xiangxiang
authors.affiliation: The Key Laboratory of Pathobiology, Ministry of Education, the College of Basic Medical Sciences, Jilin University, Changchun, Jilin 130021, P.R. China. Electronic address: liwei2006@jlu.edu.cn.
authors.forename: Li
authors.initials: L
authors.lastname: Wei