Expression of vascular permeability factor/vascular endothelial growth factor (VPF/VEGF) in meningiomas and associated peritumoral edema

Introduction: VPF or VEGF is a highly secreted mitogenic growth factor, which acts specifically on vascular endothelial cells. High affinity receptors of VPF/VEGF (KDR & FLT-1) are expressed only on endothelial cells. VPF/VEGF has been shown to be present in a number of solid tumours and to play a prominent role in tumour associated angiogenesis and the development of tumour related edema. The role of VPF/VEGF in the central nervous system has been studied in astrocytic tumours but not in meningiomas, which are the second most common primary brain tumor. These tumors although benign can be highly vascular and sometimes associated with marked peri-tumoral edema, both features potentially linked to VPF/VEGF. Methods: In this study expression of VPF/VEGF and its receptors, were examined in meningioma specimens. Results: Northern analysis, in-situ hybridization and immunohistochemistry demonstrated that VPF/VEGF was expressed in majority of meningiomas. Immunohistochemistry localized VPF/VEGF to meningothelial tumour cells but not the vascular endothelial cells. In-situ hybridization demonstrated that the receptors (KDR & FLT-1) were expressed only in endothelial cells within the tumor. In some tumours, there were subtle areas of endothelial hyperplasia, with VEGF expression in the meningothelial cells around these vessels. VPF/VEGF mRNA expression was upregulated in meningiomas associated with prominent peri-tumoral edema, with the reactive astrocytes found in these edematous areas staining for VPF/VEGF. Conclusions: This study demonstrates that VPF/VEGF and its receptors are expressed in meningiomas, and potentially contribute to the angiogenesis and associated peri-tumoral edema in these tumors.