Evaluation of Matrix Metalloproteinase 9 Serum Concentration as a Biomarker in Malignant Mesothelioma.

Background: Malignant mesothelioma (MM) is a rare, but fatal disease with few treatment options. The diagnosis and treatment response are challenging in MM. Therefore, the search for novel diagnostic and prognostic biomarkers is ongoing. The aim of our study was to investigate matrix metalloproteinase 9 (MMP9) as a potential serum biomarker of treatment response and survival in MM. We also investigated the influence of genetic polymorphisms on MMP9 serum levels.

Methods: We included 110 patients with MM that have been previously genotyped for common polymorphisms. Serum samples were collected before treatment, at the end of chemotherapy, and at the time of progression. MMP9 serum levels were measured using enzyme-linked immunosorbent assay kits. The role of serum MMP9 and polymorphisms in treatment response was determined using the nonparametric tests and logistic or Cox regression.

Results: Median serum MMP9 was 706.7 (499.6-1224.9) ng/ml before treatment, 440.5 (255.9-685.2) ng/ml after chemotherapy, and 502.8 (307.2-851.4) ng/ml at disease progression. After chemotherapy, 87 (79.8%) patients had lower serum MMP9, with the median change of -286.3 (-607.3 to -70.2) ng/ml ( < 0.001). At disease progression, 47 (65.3%) patients had lower serum MMP9 compared to pretreatment values, with the median change of -163.7 (-466.6 to 108.6) ng/ml ( = 0.001). Patients with higher performance status had higher serum MMP9 before treatment ( = 0.010). Among investigated polymorphisms, only rs17576 was associated with serum MMP9 levels before treatment ( = 0.041).

Conclusion: Median serum MMP9 levels differed significantly before and after treatment of MM, but failed to reach significance as a standalone biomarker. The contribution of MMP9 serum levels and polymorphisms to a composite diagnostic and prognostic biomarker should be further tested.