Regional specificity of matrix metalloproteinase-9 expression in the brain: voxel-level mapping in primary glioblastomas

Abstract

To investigate the anatomical specificity of matrix metalloproteinase-9 (MMP-9) expression in glioblastomas by using voxel-based neuroimaging analysis. Clinical information and preoperative magnetic resonance images of 133 patients with glioblastomas were reviewed. Evaluation of MMP-9 expression was performed by using immunohistochemistry. Tumour lesions were segmented manually basing on the structural image of each patient, then registered to a standard brain atlas. Voxel-based regression analysis was subsequently performed to identify the specific brain regions that were associated with MMP-9 expression levels. A significantly larger lesion volume of T2-hyperintensity was demonstrated in tumours with low MMP-9 expression compared to those with high MMP-9 expression (p=0.010). No significant difference was found in the lesion volumes of the contrast enhancement areas between the two groups (p=0.452). The major correlated cluster with high MMP-9 expression was identified in the right frontal lobe, while a cluster located at the posterior region of the right lateral ventricle was correlated with low MMP-9 expression. Voxel-based statistical analysis revealed the anatomical specificity of MMP-9 expression levels in glioblastoma. The identified correlation between molecular biomarkers and anatomical distribution may increase our understanding of the biological characteristics of glioblastoma and provide new insight into the molecular subtypes of glioblastoma.