Low differentiated microvascular density and low expression of platelet‐derived growth factor‐ BB ( PDGF‐BB ) predict distant metastasis and poor prognosis in clear cell renal cell carcinoma

OBJECTIVE: To examine the prognostic significance of the expression of platelet-derived growth factor-BB (PDGF-BB) and differentiated microvascular density (MVD) in patients with clear cell renal cell carcinoma (ccRCC). PATIENTS AND METHODS: We used the vascular marker cluster of differentiation 34 (CD34) to identify tumour blood vessels. The expression of PDGF-BB and CD34 was detected by immunohistochemistry (IHC) in tissue microarrays (TMAs) from 100 ccRCCs. Prognostic effects of individual parameters were calculated using Cox regression models and Harrell's concordance index (c-index). RESULTS: Higher grade and more advanced stage ccRCCs had significantly less PDGF-BB expression and differentiated MVD (P < 0.05). Higher PDGF-BB expression was an independent prognostic factor for longer survival, and moreover, the final model built by the addition of PDGF-BB expression improved the predictive accuracy for disease-free survival (c-index 0.707) compared with the clinicopathological-based model (c-index 0.695). PDGF-BB expression was positively associated with differentiated MVD assessed by Spearman correlation and factor analysis (r = 0.634, P < 0.001). CONCLUSION: PDGF-BB is as a novel and promising prognostic marker and antiangiogenic therapeutic target for the treatment of ccRCC.