Expression of Vascular Endothelial Growth Factor (VEGF) and Its Clinical Significance with Neovascularization in Conventional Renal Cell Carcinoma

Kim, Ju Nam; Song, Ki Hak; Song, Jae Mann

Abstract

PURPOSE
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 evaluate the expression of VEGF, microvessel count (MVC) and to determine their prediction efficacies for prognosis in conventional renal cell carcinomas.
MATERIALS AND METHODS
Using immunohistochemistry, the relationship between the expression of VEGF and MVC were evaluated in 60 patients with conventional renal cell carcinomas who underwent a radical nephrectomy at our hospital from 1990 to 2000. Microvessels were identified by immunostaining of endothelial cells for CD-31 antigen. The Kaplan-Meier method and log rank tests were used for univariate analysis, and Cox regression was also used for multivariate analysis.
RESULTS
VEGF was expressed on the tumor cell cytoplasm. Of 60 tumors, 23 (38.3%) were weak to strong positive for VEGF. VEGF positivity correlated with microvessel count. Mean MVCs were significantly higher in VEGF-positive tumors (19.5+/-10.4) than in VEGF-negative tumors (11.2+/-7.5). Expression of VEGF was significant correlated to stage, and MVC. The five-year survival rate was 47.2%, in VEGF positive patients, and 81.9% in VEGF negative patients (log rank p=0.02). The five-year survival rate according to MVC, the low microvessel density group (<10/HPF) was 87.5%, and the high microvessel density group (>=10/HPF) was 53.9% (log rank p=0.004). Multivariate analysis showed that expression of VEGF (hazard ratio=0.3, p=0.03) and MVD (hazard ratio=0.15, p=0.01) have a prognostic predictive value.
CONCLUSIONS
These results suggest that expression of VEGF and MVC may be appreciated as a prognostic factor in conventional renal cell carcinoma.