CORRELATION OF BASIC FIBROBLAST GROWTH-FACTOR EXPRESSION LEVELS WITH THE DEGREE OF MALIGNANCY AND VASCULARITY IN HUMAN GLIOMAS

Basic fibroblast growth factor (FGF) is a mitogen, a differentiation factor for neuroectoderm-derived cells, and a potent angiogenic factor. The authors have previously demonstrated that the messenger ribonucleic acid of basic FGF is expressed in more than 90% of human gliomas. In the present study, they examined the expression of basic FGF in human glioma tissues using immunohistochemical techniques with a mouse monoclonal antibody against human basic FGF. They also correlated the basic FGF level with the histological grades of malignancy assessed by the number of nucleolar organizer regions (NOR's). Basic FGF was detected in 18 of 19 gliomas, whereas it was undetectable in two normal brains. The expression level of basic FGF peptide increased proportionally with the degree of malignancy. There was also a tendency for the number of NOR's in glioma cells to increase in glioma samples with a high level of basic FGF expression. Furthermore, most of the cases with increased vascularity demonstrated on cerebral angiograms showed a relatively high level of basic FGF expression of tumor cells and a large number of NOR's in endothelial cells in tumor tissues. These results suggest that basic FGF is actually produced in most gliomas and is involved in tumorigenesis and malignant progression as an autocrine growth factor. Moreover, basic FGF may play an important role in tumor neovascularization as a paracrine angiogenic factor.