Matrix metalloproteinase-9 as a prognostic factor in gastric cancer: a meta-analysis.

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.

METHOD

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.