VASCULAR ENDOTHELIAL GROWTH-FACTOR AND NEOVASCULARIZATION IN ASTROCYTIC TUMORS

It has been widely recognized that the vascular structure is an import ant factor when making a histopathological diagnosis and assessing the malignancy potential, especially of astrocytic tumors. The vascular e ndothelial growth factor (VEGF), which is thought to be regulated by t he p53 gene, is a regulation factor for tumor neovascularization. The relationship between VEGF distribution and neovasculature was studied in 42 cases of astrocytic tumors (grades 1-4), which were obtained fro m surgical material, and the St Anne-Mayo grading system was applied. The relationship between the labeling indices (LI) of VEGF and LI of p 53 protein in tumor cells was also studied using immunohistochemistry. The VEGF LI in high-grade malignancy potential tumors, such as grade 3 and grade 4 tumors, was significantly higher than those that were lo w grade. In grade 4 tumors, a significant correlation between the VEGF LI and the proliferation indices of endothelial cells of neovasculatu res was observed. No significant correlation was noted between p53 LI and VEGF LI, as well as p53 LI and histopathological grade. In astrocy tic tumors, expression of VEGF may be correlated to tumor neovasculari zation, and can be considered as an indicator of malignancy potential in astrocytic tumors.