VEGF/VEGFR2 and PDGF-B/PDGFR-β expression in non-metastatic renal cell carcinoma: a retrospective study in 1,091 consecutive patients.

PURPOSE We aimed to investigate the correlations between the expression of VEGF, PDGF-B, and their receptors (VEGFR2 and PDGFR-β) with pathologic stage or cell type in non-metastatic renal cell carcinoma. MATERIALS AND METHODS VEGF, VEGFR2, PDGF-B, and PDGFR-β protein expression were evaluated immunohistochemically in prospectively collected 1,423 tumour samples obtained during radical or partial nephrectomy at a tertiary referral center. Intensity of expression was quantified on a scale of 0 to 3, and was compared among renal cell carcinoma cell types. RESULTS The study cohort consisted of 1,091 patients, of mean age 54 years, including 968 (88.7%) with clear cell, 82 (7.5%) with papillary, 31 (2.8%) with chromophobe, 4 (0.4%) with unclassified, and 6 (0.5%) with other types of renal cell carcinoma. VEGF expression increased with higher T and N stage and Fuhrman nuclear grade. PDGFR-β expression was highest in clear cell renal cell carcinoma, whereas VEGF and PDGF-B expression were highest in papillary renal cell carcinoma. After adjusting for T stage and Fuhrman nuclear grade using multivariate logistic regression analysis, VEGF (OR = 3.57, P < 0.001), VEGFR2 (OR = 1.82, P = 0.017), and PDGF-B (OR = 2.46, P = 0.019) expression were significantly greater in papillary than in clear cell type. CONCLUSIONS Our results indicate that the cytoplasmic expression of VEGF, VEGFR2, PDGF-B, and PDGFR-β in RCC tumour cells is different in various pathologic stage and cell type. Notably, VEGF and PDGF-B expression are higher in papillary than in clear cell renal cell carcinoma. Further studies using quantitative measurement of proangiogenic factors in tumour cell are needed.