The highly invasive growth of glioblastomas may be a consequence of an abnormal profile of proteinases and proteinase inhibitors involved in remodeling of the basement membrane and normal vasculature. We have detected a 1.5-3-fold increase in the transcription of gelatinase A and TIMP-2 (Tissue Inhibitor of Metalloproteinase) in glioblastomas as compared to the normal brain tissue. Increased expression of gelatinase A and TIMP-2 in these tumors was also evident by immunohistochemical analysis. Our data suggest that increased expression and perturbation of the balance between metalloproteinases and their inhibitors that are involved in extracellular matrix remodeling and angiogenesis may contribute to the invasive phenotype of glioblastomas.