Prognostic significance of platelet-derived growth factor receptor-β expression in localized clear cell renal cell carcinoma

We investigated the expression status of vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF)-B and their receptors in organ-confined clear cell renal cell carcinoma (ccRCC) to evaluate their prognostic significance after radical surgery. In 758 consecutive patients diagnosed with pT1-2N0 ccRCC between 2007 and 2012, we prospectively investigated the expression levels of VEGF, PDGF-B, VEGF receptor (VEGFR) and PDGF receptor (PDGFR)-beta via immunohistochemistry. Clinicopathologic parameters and expression of the angiogenic factors were analyzed with respect to recurrence-free survival (RFS) after nephrectomy. The median follow-up was 29.5 months (IQR 21.5, 39.6) after surgery. Partial nephrectomy had been performed in 48.5 % of the patients, and tumors were staged as pT1a in 514 (67.8 %), pT1b in 192 (25.3 %) and pT2 in 52 (6.9 %). VEGF, PDGF and their receptors were identified in the cytoplasm and membranes of the tumor cells. Expression level of VEGFR inversely correlated with both tumor size (r = -0.076, p = 0.014) and nuclear grade (r = -0.297, p = 0.004). As for PDGF-B, the expression level showed an inverse correlation with tumor size (r = -0.216, p < 0.001) while PDGFR-beta inversely correlated with nuclear grade (r = -0.341, p = 0.001). On multivariate analysis, age, pathologic stage, nuclear grade and PDGFR-beta expression (high vs. low or none, HR 3.121 95 % CI 1.300-7.493, p = 0.011) were independently prognostic of RFS after nephrectomy. In organ-confined ccRCC, high expression of PDGFR-beta was independently predictive of poorer RFS after nephrectomy.