High Level of Circulating Endothelial Progenitor Cells Positively Correlates with Serum Vascular Endothelial Growth Factor in Patients with Renal Cell Carcinoma

Abstract

Although accumulated evidence indicates that circulating endothelial progenitor cells contribute to tumor neovascularization, to our knowledge the level of these cells and its correlation with serum vascular endothelial growth factor in patients with renal cell carcinoma have not been studied. We measured this level and investigated its clinical significance in patients with renal cell carcinoma. The level of circulating endothelial progenitor cells (percent of total peripheral blood mononuclear cells) was quantified by assaying the CD45(-)CD34(+)vascular endothelial growth factor receptor 2(+) cell phenotype in 53 patients with renal cell carcinoma, 33 with benign renal tumors and 40 healthy controls. Serum vascular endothelial growth factor was quantified. The mean circulating endothelial progenitor cell level in patients with renal cell carcinoma was 0.281%, significantly higher than in patients with benign renal tumors and healthy controls (0.073% and 0.076%, respectively, each p <0.001). Patients with stage III-IV renal cell carcinoma had a statistically higher level of these cells than those with stage I-II (0.339% vs 0.243%, p <0.001). The mean level in patients with renal cell carcinoma greater than 7 cm was 0.331%, significantly higher than in those with tumors 4 or less and 4 to 7 cm (0.225% and 0.231%, respectively, each p <0.001). Mean serum vascular endothelial growth factor in patients with renal cell carcinoma was higher than in patients with benign renal tumors and healthy controls (315.5 vs 34.6 and 26.9 pg/ml, respectively, each p <0.001). The preoperative circulating endothelial progenitor cell level positively correlated with serum vascular endothelial growth factor in patients with renal cell carcinoma (r = 0.710, p <0.001). Levels of these cells and of vascular endothelial growth factor significantly decreased postoperatively compared to preoperatively (0.081% vs 0.297% and 31.69 vs 310.70 pg/ml, respectively, each p <0.001). A high circulating endothelial progenitor cell level was found in patients with renal cell carcinoma, which positively correlated with serum vascular endothelial growth factor. Results support the potential use of circulating endothelial progenitor cells as a novel biomarker for renal cell carcinoma.