Prognostic value of matrix metalloproteinase 9 expression in patients with non-small cell lung cancer

Abstract Background The role of matrix metalloproteinase 9 (MMP-9) expression in non-small cell lung cancer (NSCLC) remains controversial. We performed a systematic review of the literature with meta-analysis. Methods Electronic databases were used to identify published studies before December 1, 2011. Pooled hazard ratio (HR) with 95% confidence interval (95% CI) was used to estimate the strength of the association between MMP-9 expression survival of NSCLC patients. Heterogeneity and publication bias were also assessed. Results The final analysis of 2029 NSCLC cases from 17 studies is presented. The combined HR of 1.84 (95% CI: 1.62–2.09) suggested that MMP-9 over-expression had a poor prognosis in patients with NSCLC. Subgroup analyses also detected significant association. Heterogeneity and publication bias was absent in current meta-analysis. Sensitivity analyses suggested that the summary statistics obtained should approximate the actual average. Conclusion High MMP-9 expression is associated with a poor prognosis in patients with NSCLC.