Vascular endothelial growth factor - Its relation to neovascularization and their significance as prognostic factors in renal cell carcinoma

Angiogenesis is a series of processes that include endothelial proliferatio n, migration and tube formation. Vascular endothelial growth factor (VEGF) is regarded as a potent mediator of angiogenesis, vascular permeability and tumor cell growth in renal cell carcinoma. This study was designed to eval uate the expression of VEGF and the microvessel count (MVC) and to determin e their prediction efficacies for prognosis in renal cell carcinoma. The re lationship between the expression of VEGF and MVC were evaluated immunohist ochemically in 50 patients with renal cell carcinoma who received a radical nephrectomy at Wonju Christian Hospital between 1989 and 1997. Microvessel s were identified by immunostaining endothelial cells for CD-31 antigen. Th e mean follow-up was 96 months (3 - 133 months). Overall 5-year survival ra te was 71.5%. VEGF was expressed in the tumor cell cytoplasm. Of the 50 tum ors, 23 (46%) were weak to strongly positive for VEGF but 27 (54%) were unr eactive. The respective 5-year survival rates for patients with positive an d negative expressions of VEGF were 70% and 73% (P > 0.05). The overall mea n MVC was 13.4 in a 400x field. Mean MVCs were significantly higher in VEGF -positive tumors (17.6 +/- 12.1) than in V-EGF-negative tumors (9.9 +/- 5.4 ). and the MVCs of the high vascular density group and the low vascular den sity groups were significantly different. The 5-year survival rates of pati ents with high vascular density and low vascular density were 59% and 86%. The median survival period for patients with MVCs higher than or equal to 1 0 vessels/field was 85 months, whereas for those with MVCs lower than 10 ve ssels/field the median survival time was 102 months. These results suggest that MVC may be a better prognostic factor in renal cell carcinoma than the expression of VEGF.