Longitudinal prospective study of matrix metalloproteinase-9 as a serum marker in gliomas

The objective of this study was to evaluate if longitudinal measurements of serum matrix metalloproteinase-9 (MMP-9) correlated with disease status or survival in adults with gliomas. Serum samples were collected prospectively and concurrently with MRI scans at multiple time points during the course of the disease. MMP-9 levels were determined by ELISA and correlated with radiographic disease status and survival. Forty-one patients with low-grade gliomas, 105 with anaplastic gliomas, and 197 with glioblastoma enrolled in this study from August 2002 to September 2008. A total of 1,684 serum samples (97.1% of all MMP-9 samples) had a matching MRI scan. No statistically significant association was observed between levels of serum MMP-9 and radiographic disease status in low-grade gliomas (P = 0.98), anaplastic gliomas (P = 0.39) or glioblastomas (P = 0.33). Among patients with glioblastoma, longitudinal increases in MMP-9 had a weak association with shorter survival (HR = 1.1 per each doubling in MMP-9 levels, 95% CI, 1.0-1.3, P = 0.04) but they were not independently associated with survival when adjusted for age, extent of resection, and performance status. Changes in serum MMP-9 were not associated with survival in the anaplastic glioma cohort. Serum MMP-9 showed no utility in determining glioma disease status and was not a clinically relevant prognostic marker of survival.