Validation of the diagnostic and prognostic relevance of serum MMP-7 levels in renal cell cancer by using a novel automated fluorescent immunoassay method.

Purpose: Despite encouraging results in other cancers, in renal cell cancer, no consensus exists regarding the diagnostic and prognostic relevance of MMP-7. The aim of this study was to assess the diagnostic and prognostic potential of serum MMP-7 levels in renal cell cancer. Furthermore, parallel to the widely used ELISA method, we tested a new, fluid-phase, fluorescent immunoassay (B.R.A.H.M.S KRYPTOR®) for the quantitation of MMP-7.

Methods: We analyzed the serum samples of 174 individuals (77 patients and 97 age-matched healthy controls) by a commercially available sandwich ELISA and by a novel, automated, fluid-phase immunofluorescent assay (B.R.A.H.M.S KRYPTOR®). Results were correlated with the clinicopathological and follow-up data.

Results: MMP-7 concentrations showed a high concordance level (R (2) = 0.979) between the two methods (p < 0.001). Serum MMP-7 concentrations were significantly higher in patients compared to controls. At a cutoff value of 3.15 ng/ml, a specificity and a sensitivity of 70 and 82 % for the detection of RCC was found. Patients with metastasis had significantly higher MMP-7 levels as those without metastasis (p = 0.038 by KRYPTOR, p = 0.011 by ELISA). High MMP-7 levels proved to be independently associated with shorter overall, disease-specific and metastasis-free survival, regardless of the analytical method.

Conclusions: Based on these results, serum MMP-7 levels have both diagnostic and prognostic potential. The KRYPTOR method provided comparable results to the standard ELISA analysis, with a high concordance level and can therefore be considered as a surrogate method. Its flexibility and automated operation make the KRYPTOR MMP-7 assay suitable for routine laboratory use in the daily practice.