Expression of vascular endothelial growth factor (VEGF) and its receptor (Flk-1) in nephroblastoma

Abstract

Objective To investigate the expression and clinical significance of vascular endothelial growth factor (VEGF) and its receptor Flk-1 in nephroblastoma. To assess whether tumor microvessel density (MVD) immunoreactivity, determined by the CD34 antigen, is related to the expression of VEGF and Flt-1. Methods Immunohistochemical staining (SABC) was used to examine MVD and the expression of VEGF, Flk-1 in 33 nephroblastoma tissues, 33 paracancer renal tissues and 6 normal kidney tissues. The relation between the expressions of VEGF, Flk-1 and MVD was analyzed in different clinical stage and pathology type, Patients were treated preoperatively with chemotherapy and mean follow up was 34 months. Results The positive rates of VEGF and Flk-1 in nephroblastoma tissues were 81.8% and 69.7%, the positive rates of VEGF and Flk-1 in paracancer renal tissues were 9.1% and 6.1%, the expressions of VEGF and Flk-1 were negative in all normal kidney. The differences between the three groups were statistically significant (P＜0.05). In nephroblastoma tissues,the expression of VEGF correlated to both Flt-1 and MVD (P＜0.05), and the expression of Flt-1 correlated to MVD (P＜0.05). In addition, the expressions of VEGF and Flk-1 were increased in clinical stage Ⅲ and poor prognosis. Conclusions These results indicate that VEGF and Flk-1 may play an important role in nephroblastoma angiogenesis. Increased expression of VEGF and Flk-1 in nephroblastoma correlated with tumor stage, clinical progression and tumor related death. VEGF and Flk-1 protein expression are closely related to MVD and seem to be a important predictor for poor prognosis in treated patients with nephroblastoma. Key words: Nephroblastoma; Vascular endothelial growth factor; Receptors,vascular endothelial growth factor