Immunohistochemical study of fibronectin in human glioma and meningioma

The presence of fibronectin (FN) and glial fibrillary acidic protein (GFAP) in two astrocytomas, 17 glioblastomas, and five meningiomas was studied by indirect immunoperoxidase staining of formalin-fixed and paraffin-embedded surgical specimens. Angiogenesis in tumor was scored by the microscopic angiogenesis grading system (MAGS), and plasma FN levels were measured by single radial immunodiffusion. In astrocytomas and glioblastomas, GFAP-positive tumor cells had no FN expression and FN was confined to proliferating vessel walls and the leptomeninges, showing a mutually exclusive FN and GFAP expression. GFAP-positive tumor cells were occasionally surrounded by a network of FN-positive matrix produced by cells derived from the leptomeninges or blood vessels. In meningiomas, FN expression was found in vessel walls and meningioma cells including whorl formations and psammoma bodies. In general, deep immunoperoxidase staining for FN was shown in the endothelial cells and the psammoma bodies. Plasma FN levels were correlated significantly not to the degree of leptomeningeal proliferation but to the MAGS scores in gliomas.