title: Prognostic significance of COX-2 immunohistochemical expression in colorectal cancer: a meta-analysis of the literature.
abstract: BACKGROUND
  Cyclooxygenase-2 (COX-2) is believed to be an important enzyme in the pathogenesis of colorectal cancer (CRC). Correlations between the expression of COX-2 with tumor growth and distant metastasis have become an issue; thus, attention has been paid to COX-2 as a prognostic factor. Various studies examined the relationship between COX-2 immunohistochemistry (IHC) overexpression with the clinical outcome in patients with colorectal cancer, but yielded conflicting results. The prognostic significance of COX-2 overexpression in colorectal cancer remains controversial.
  
  
  METHODS
  Electronic databases updated to October 2012 were searched to find relevant studies. A meta-analysis was conducted with eligible studies which quantitatively evaluated the relationship between COX-2 overexpression and survival of patients with colorectal cancer. Survival data were aggregated and quantitatively analyzed.
  
  
  RESULTS
  We performed a meta-analysis of 23 studies (n  =  4567 patients) that evaluated the correlation between COX-2 overexpression detected by IHC and survival in patients with colorectal cancer. Combined hazard ratios suggested that COX-2 overexpression had an unfavorable impact on overall survival (OS) (HR [hazard ratio]  =  1.193, 95% CI [confidence interval]: 1.02 ∼ 1.37), but not disease free survival (DFS) (HR  =  1.25, 95% CI: 0.99 ∼ 1.50) in patients with colorectal cancer.
  
  
  CONCLUSIONS
  Cox-2 overexpression in colorectal cancer detected by IHC appears to have slightly worse overall survival. However, the prognostic value of COX-2 on survival in colorectal cancer still needs further large-scale prospective trials to be clarified.
authors.affiliation: Department of Thoracic Oncology, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Peng
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhou
authors.forename: Yina
authors.initials: Y
authors.lastname: Wang
authors.forename: Haibo
authors.initials: H
authors.lastname: Mou
authors.forename: Qiong
authors.initials: Q
authors.lastname: Zhao
mesh_terms: D015179:Colorectal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000401:mortality; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D056726:Genetic Association Studies; D006801:Humans; D007150:Immunohistochemistry; D011379:Prognosis; D017594:Publication Bias
chemical_list: D051546:Cyclooxygenase 2