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

Abstract

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.

The VEGF/VEGF-R Axis in Sporadic Vestibular Schwannomas Correlates with Irradiation and Disease Recurrence

“…Moreover, we found that all of the tumors expressed VEGFR-1/Flt and VEGFR-2/Flk as well as the coreceptor NP1. Expression of VEGF and of all three receptors was identified both on tumor cells and on endothelial cells of tumor-associated vessels, which is in line with previous reports [5,7,26,27]. This finding may suggest a cross-talk between tumor cells and vessels in a paracrine-stimulating manner.…”

“…Moreover, VEGF has been reported to act as a survival factor for Schwann cells [10]. Accordingly, upregulated VEGF expression has been previously demonstrated in VS [5,7,24,25,26]. In our present study also, all samples expressed VEGF.…”

“…Vascularization and new blood vessel development are an important aspect of solid tumor growth in general [3] and have also been involved in the specific case of VS growth [4,5,6,7]. Among the numerous proangiogenic growth factors, the vascular endothelial growth factor (VEGF) is considered to be a major regulator of angiogenesis.…”

Human Schwannomas Express Activated Platelet-Derived Growth Factor Receptors and c-kit and Are Growth Inhibited by Gleevec (Imatinib Mesylate)

“…Schwannomas do not harbor the bcr-abl oncogenic translocation, but expression of PDGFRs and growth factors has been previously noted (13)(14)(15)(16)(17)(18). To determine if c-kit, PDGFR-α, and PDGFR-β are expressed, activated, and play a functional role in promoting growth, we used human surgical schwannoma specimens as well as the HEI-193 immortalized human schwannoma cell line.…”

“…In contrast to initiation, the molecular factors that promote the usual indolent growth of schwannomas and the occasional growth spurts are not well studied. Aberrant expression and activation of growth factors and receptors are prime candidates and are potential biological targets, which may be therapeutically exploited to either negate or delay active intervention in selected cases (13)(14)(15)(16)(17)(18).…”