title: Matrix metalloproteinase-9 as a prognostic factor in gastric cancer: a meta-analysis.
abstract: BACKGROUND
  Matrix metalloproteinase-9 (MMP-9) is associated with disruption of basement membranes of blood vessels and promotion of metastasis through the lymphatics. However, its prognostic value for survival in patients with gastric cancer remains controversial.
  
  
  METHODS
  We therefore conducted a meta-analysis of the published literature in order to clarify the impact of MMP-9. Clinical studies were selected for further analysis if they provided an independent assessment of MMP-9 in gastric cancer and reported analysis of survival data according to MMP-9 expression.
  
  
  RESULTS
  A total of 11 studies, covering 1700 patients, were included for meta- analysis. A summary hazard ratio (HR) of all studies and sub-group hazard ratios were calculated. The combined HR suggested that a positive MMP-9 expression had an impact on overall survival: 1.25 (95% confidence interval 1.11-1.40) in all eligible studies; 1.13 (1.06-1.20) in 8 studies detecting MMP-9 by immunohistochemistry; 1.36 (1.12-1.65) in 7 studies from Asia. Only one study for DFS showed a significant impact on disease free survival (HR 1.73, 95%CI 1.27-2.34).
  
  
  CONCLUSIONS
  Our findings suggested that MMP-9 protein expression might be a factor for a poor prognosis in patients with gastric cancer. However, the association was rather weak, so that more prospective studies should further explore the prognostic impact of MMP-9 mRNA and correlations between MMP-9 and clinicopathological characteristics.
authors.affiliation: Department of Medical Oncology, Cancer Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China.
authors.forename: Qiong-Wen
authors.initials: QW
authors.lastname: Zhang
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.forename: Ru
authors.initials: R
authors.lastname: Chen
authors.forename: Yu-Quan
authors.initials: YQ
authors.lastname: Wei
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.forename: Hua-Shan
authors.initials: HS
authors.lastname: Shi
authors.forename: Yu-Wei
authors.initials: YW
authors.lastname: Zhao
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D018572:Disease-Free Survival; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D009362:Neoplasm Metastasis; D016016:Proportional Hazards Models; D013274:Stomach Neoplasms / Q000201:enzymology* / Q000401:mortality*
chemical_list: D014408:Biomarkers, Tumor; D020780:Matrix Metalloproteinase 9