Microvessel area of immature vessels is a prognostic factor in renal cell carcinoma

Objectives: To analyze the presence of immature vessels as a predictive factor of prognosis in patients with renal cell carcinoma. Methods: Tissue samples were obtained from 50 renal cell carcinoma patients who underwent radical nephrectomy, and the blood vessels were stained using antibodies to cluster of differentiation 34 and a-smooth muscle actin. Immature vessels were defined as those positive for cluster of differentiation 34, and mature vessels as those positive for both cluster of differentiation 34 and a-smooth muscle actin. The extent of vascularization was quantified by calculating the microvessel area and microvessel density. Results: The microvessel area of immature vessels was positively associated with tumor grade (P < 0.0001), T stage (P < 0.0001) and American Joint Committee on Cancer stage (P < 0.0001), and was significantly higher in tumors with metastasis than in those without metastasis (P < 0.0001). The microvessel density did not associate with tumor grade or T stage. The disease-free survival and overall survival were significantly shorter in patients with high microvessel area. Conclusions: The microvessel area of immature vessels seems to be associated with renal cell carcinoma aggressiveness, suggesting this might be considered as a novel prognostic factor in patients with these tumors.