title: Association between raf kinase inhibitor protein loss and prognosis in cancers of the digestive system: a meta-analysis.
abstract: BACKGROUND
  Loss of Raf kinase inhibitor protein (RKIP) may contribute to metastasis in a variety of human cancers. Many studies have evaluated whether loss of RKIP expression is a prognostic factor for survival in cancers of the digestive system, however, its predictive value remains controversial. Thus, we performed a meta-analysis to obtain a more comprehensive estimate of the prognostic value of RKIP expression in digestive system cancers.
  
  
  METHODS
  Studies were identified by searching multiple electronic databases through December 12, 2013, and by reviewing reference lists of obtained articles. Studies reported hazard ratios (HRs) with 95% confidence intervals (CIs) for the association between RKIP and overall survival (OS) and disease-free survival (DFS) in cancers of the digestive system were eligible, including esophageal cancer, gastric cancer, colorectal cancer and pancreatic cancer.
  
  
  RESULTS
  Nineteen studies involving approximately 3700 participants were included in the final analysis. The pooled results suggested that loss of RKIP expression was associated with unfavorable OS (HR 0.55, 95% CI 0.46-0.65) and DFS (HR 0.46, 95% CI 0.30-0.62) among patients with digestive system cancers, whereas the difference was not statistically significant in pancreatic cancer specifically (OS, HR 0.76; 95% CI 0.51-1.01; DFS, HR 0.71; 95% CI 0.28-1.13).
  
  
  CONCLUSIONS
  Loss of RKIP expression might be an independent indicator of poor prognosis in patients with digestive tract cancers, which includes esophageal cancer, gastric cancer and colorectal cancer. More studies are needed to further clarify the prognostic value of RKIP in pancreatic cancer. Future studies, preferably large prospective studies utilizing formal marker assessment processes, are needed to establish the prognostic value of RKIP before these results can be clinically applied.
authors.affiliation: Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China.
authors.forename: Min
authors.initials: M
authors.lastname: Yu
authors.affiliation: Department of Neurology, The Southern Medical University, Guangzhou, Guangdong, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Department of Oncology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China.
authors.forename: Jiang-Wu
authors.initials: JW
authors.lastname: Ding
authors.affiliation: Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China.
authors.forename: Chuan
authors.initials: C
authors.lastname: Xie
authors.affiliation: Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China.
authors.forename: Nong-Hua
authors.initials: NH
authors.lastname: Lu
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D004064:Digestive System / Q000378:metabolism / Q000473:pathology; D018572:Disease-Free Survival; D005770:Gastrointestinal Neoplasms / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D008875:Middle Aged; D049488:Phosphatidylethanolamine Binding Protein / Q000378:metabolism*; D011379:Prognosis
chemical_list: D014408:Biomarkers, Tumor; C511482:PEBP1 protein, human; D049488:Phosphatidylethanolamine Binding Protein
keywords: Cancers of the digestive system; disease-free survival (DFS); meta-analysis; overall survival (OS); raf kinase inhibitor protein (RKIP)