Different isoform patterns for vascular endothelial growth factor between clear cell and papillary renal cell carcinoma

OBJECTIVE To investigate the protein expression of vascular endothelial growth factor (VEGF) isoforms in relation to the clinical course in patients with different renal cell carcinoma (RCC) types, as angiogenesis is essential for tumour growth and metastasis. PATIENTS AND METHODS Western blots were assayed of protein extracts from tumour and concomitant kidney cortex samples from 96 patients. The levels of VEGF(189), VEGF(165), and VEGF(121) isoforms were correlated with clinicopathological characteristics and survival. RESULTS VEGF(189) levels were significantly higher in kidney cortex and chromophobe RCC than in papillary and conventional RCC. In papillary RCCs, VEGF(189) levels correlated inversely with tumour stage and tumour size. VEGF(165) levels were higher in kidney cortex than in RCC, but there was no difference among the RCC types. VEGF(121) expression was associated with less advanced tumour stage in conventional RCC. Using multivariate analysis, VEGF(189) remained as an independent prognostic factor for patients with papillary RCC. CONCLUSIONS VEGF(189) was associated with tumour progression; in papillary RCC, VEGF(189) was a significant independent prognostic factor. VEGF protein isoform patterns differed among the specific RCC types. Additional knowledge is essential to design new antiangiogenic therapies for all RCC types.