Matrix metalloproteinase‐7 as a marker of metastasis and predictor of poor survival in bladder cancer

Matrix metalloproteinases (MMPs) play an important role in tumor progression and metastasis. Here, we investigated the prognostic relevance of MMP-7 in urinary bladder cancer. MMP-7 gene expression was measured in tissue samples of 101 patients using quantitative real-time PCR. Circulating MMP-7 serum levels of 98 individuals (79 patients and 19 controls) were analyzed by enzyme-linked immunosorbent assay. The results were compared with the clinical follow-up data, performing Kaplan-Meier log-rank test as well as univariate and multivariate Cox analysis. In representative cases, immunohistochemical analysis for MMP-7 was performed. We detected significantly elevated MMP-7 levels both in tissue and serum samples of patients with metastatic disease (P = 0.001 and P = 0.002). Multivariate analysis revealed that high MMP-7 tissue expression and serum concentration are stage- and grade-independent predictors of both metastasis-free (hazard ratio [HR] = 3.80, 95% confidence interval [CI], 1.29-11.23, P = 0.016, and HR = 2.53, 95% CI, 1.01-6.37, P = 0.048) and disease-specific survival (HR = 1.89, 95% CI, 1.00-3.55, P = 0.050 and HR = 1.95, 95% CI, 1.03-3.71, P = 0.041). Based on these findings, we conclude that MMP-7 is a promising marker to detect present and to predict future metastasis. Serum MMP-7 analysis provides information about the risk of metastasis before surgery which could help to optimize therapeutic procedures. Furthermore, high MMP-7 tissue and/or serum levels could identify patients most likely to benefit from early adjuvant chemotherapy.