Expression of Vascular Endothelial Growth Factor and Basic Fibroblast Growth Factor in Sporadic Vestibular Schwannomas Correlates to Growth Characteristics

Hypothesis: Expression of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) may have an impact on the growth characteristics of sporadic vestibular schwannomas (VSs). Background: Vestibular schwannoma is a benign, slow-growing neoplasm that accounts for 6% of all intracranial tumors. The biological backgrounds for neoplastic growth and especially for the various growth patterns of VS remain largely unknown. Because several angiogenic and cytotrophic factors have been described to be involved in the growth of malignant tumors, we initiated this study to examine 2 major representatives of such growth factors in VS and their possible correlation to the growth characteristics of sporadic VSs. Methods: Surgical specimens from 17 patients with sporadic VS were examined, and the expression of 2 major angiogenic and neurotrophic factors, bFGF and VEGF, was quantitatively analyzed at the mRNA and protein levels. The microvessel density (MVD) was defined by CD31 staining. Results: All tumors showed expression of bFGF and VEGF at both the mRNA and protein levels. The mRNA expression and the protein expression of both growth factors correlated positive to tumor volume, to tumor growth index, and to MVD. Conclusion: The bFGF and VEGF mRNA expression and the bFGF and VEGF protein expression in sporadic VS correlates to the tumour volume, to the tumor growth index, and to the MVD. This might indicate an angiogenic and neurotrophic influence of these factors and a possible involvement in the growth of sporadic VS.