MMP2 and glioblastoma: In contrast, VEGF and MMP-2 and -9 levels were not significantly increased by carbon ion radiation; indeed, VEGF secretion was reduced at 4.0 Gy (Fig. 4), implying that carbon ions may suppress glioblastoma angiogenicity and tumorigenicity by modulating VEGF production and release into the tumor microenvironment.