Expression of vascular endothelial growth factor in diffuse malignant pleural mesothelioma

Angiogenesis is an important part of normal and pathological processes, inc luding tumour growth, metastasis, inflammation and wound healing. VEGF is t he best known angiogenic factor, implicated in tumour-associated microvascu lar hyperpermeability and carcinogenesis. We investigated 103 malignant ple ural mesotheliomas, analysing the expression of vascular endothelial growth factor using immunohistochemistry and insitu hybridization. The grade of m icrovessel density was assessed with the aid of anti-factor-VIII antibodies . An increased expression of VEGF was found in biphasic and epithelioid mes otheliomas, correlating in a statistically significant manner (P<0.042). In situ hybridization confirmed the specificity of VEGF mRNA expression. There was a robust correlation between VEGF expression and increased microvessel density (P<0.001), and positive mesotheliomas had significantly higher mic rovessel densities than negative specimens. There was also a significant co rrelation between microvessel density and histological pattern. As growth p attern tended towards biphasic and sarcomatoid mesotheliomas the density of micovessels decreased (P<0.05).