Elevated serum matrix metalloproteinase 7 levels predict poor prognosis after radical prostatectomy

Elevated matrix metalloproteinase-7 (MMP-7) tissue expression and serum concentration have been shown to be associated with cancer progression and metastasis. The aim of our study was to assess the prognostic value of preoperative circulating MMP-7 levels in serum samples of patients with clinically localized prostate cancer. Furthermore, we compared the serum MMP-7 levels between patients with organ confined and metastatic prostate cancer. MMP-7 levels were measured in 93 patients with localized prostate cancer, 13 patients with distant bone metastasis and in sera of 19 controls using enzyme-linked immunosorbent assay. The results were compared to the clinical follow-up data. We did not find any significant difference in MMP-7 serum levels between patients and controls (p = 0.268). Circulating MMP-7 serum concentration was significantly elevated in patients with distant metastasis (p < 0.001). For the detection of distant prostate cancer metastasis, using a cut-off value of 3.7 ng/ml, a specificity of 69% and a sensitivity of 92% were observed. Multivariate analysis identified high MMP-7 serum concentration as an independent risk factor for prostate cancer-related death both in a preoperative and a postoperative model (p = 0.003 and 0.018, respectively). Furthermore, the evaluation of predictive models revealed that addition of serum MMP-7 levels to the preoperatively available predictors improves prognostic accuracy (the concordance index increased from 0.631 to 0.734 when MMP-7 was included). Based on these, we concluded that MMP-7 is a potential marker to identify patients with metastatic prostate cancer. In clinically localized prostate cancer, MMP-7 may provide independent prognostic information, thereby helping to optimize therapy decisions.