title: Prognostic and clinical significance of claudin-1 in colorectal cancer: A systemic review and meta-analysis.
abstract: BACKGROUND
  The current reports on the association of claudin-1 expression with colorectal cancer (CRC) result were controversial. Thus, we conducted a meta-analysis to assess the correlation between claudin-1 expression and the clinical parameters and assess the prognostic value of claudin-1 in CRC.
  
  
  METHODS
  Systematic searches on PubMed, Embase, Elsevier, CNKI (China National Knowledge Infrastructure), Wanfang data and Cochrane Library prior to August 2016 were performed. The pooled odds ratio (OR) with its 95% confidence interval (95 %CI) was used to assess association between claudin-1 expression and clinical parameters of CRC patients, and to assess association between claudin-1 expression and the prognostic value of CRC patients.
  
  
  RESULTS
  Eight studies with a total of 1146 CRC patients were included. Overall, the pooled results showed that low expression of claudin-1 was associated with TNM III-IV stage of CRC patients (OR: 1.714, 95%CI: 1.215-2.418, P = 0.002). Low expression of claudin-1 was also associated with a poor survival in CRC patients (one year survival rate: OR: 2.112, 95%CI: 1.028-4.339, P = 0.042; three years survival rate: OR: 1.501, 95%CI: 1.030-2.186, P = 0.035; five years survival rate: OR: 1.794, 95%CI: 1.139-2.439, P = 0.000). Whereas, low expression of claudin-1 is not associated with gender (OR: 1.259, 95%CI: 0.957-1.657, P = 0.100), tumors' differentiation (OR: 1.317, 95%CI: 0.916-1.892, P = 0.137), depth of invasion (OR: 1.016, 95 %CI: 0.701-1.472, P = 0.935) and lymph node metastasis group (OR: 1.286, 95% CI: 0.982-1.684, P = 0.06) of CRC.
  
  
  CONCLUSIONS
  Low expression of claudin-1 is associated with TNM III-IV stage and poor prognosis of CRC patients. Low expression of claudin-1 is not associated with gender, tumors' differentiation depth of invasion and lymph node involvement of CRC patients.
authors.affiliation: Dalian Medical University, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Jiang
authors.affiliation: Dalian Medical University, China.
authors.forename: Long
authors.initials: L
authors.lastname: Yang
authors.affiliation: Dalian Medical University, China.
authors.forename: He
authors.initials: H
authors.lastname: Huang
authors.affiliation: Dalian Medical University, China.
authors.forename: Bai-Ying
authors.initials: BY
authors.lastname: Liu
authors.affiliation: Department of Gastrointestinal Surgery, The Dalian Municipal Center Hospital Affiliated of Dalian Medical University, China. Electronic address: zushanghai@163.com.
authors.forename: Guo
authors.initials: G
authors.lastname: Zu
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism*; D062445:Claudin-1 / Q000378:metabolism*; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D008207:Lymphatic Metastasis; D009367:Neoplasm Staging; D016017:Odds Ratio; D011379:Prognosis; D016019:Survival Analysis
chemical_list: D014408:Biomarkers, Tumor; D062445:Claudin-1
keywords: Claudin-1; Colorectal cancer; Meta-analysis; Prognosis