VASCULAR SURFACE-DENSITY IN RENAL-CELL CA RCINOMA - MORPHOMETRIC ASSESSMENT OF TUMOR VASCULARIZATION

Experimental and clinical evidence exists showing that tumor growth, l ocal recurrence and metastasis in progressive disease are dependent up on tumor angiogenesis. Quantification of microvessels as a measure of angiogenesis might be one of the most powerful prognostic tools availa ble based on the assumption that metastatic potential increases with e nhanced vascularization. Vascular surface density (VSD: dimension mu m (-1)) expressing the amount of surface area of blood vessels contained in a unit of tissue volume was calculated in 79 renal cell carcinomas of different nuclear grades (G1: n = 16; G2: n = 42; G3: n = 21). Ves sel walls were highlighted by immunostaining endothelial cells for Ule x-Europaeus-Antigen (UEA). VSD was calculated using an ocular test gri d evaluating 10 randomly selected areas for each tumor at x400 magnifi cation. In contrast to findings in other tumors we observed a signific ant reduction of vascular density with decreasing differentiation of t umor tissue, poorly differentiated RCC (G3) disclosing to lowest value of vessel surface per volume. As the mean values of Vascular surface density in normal renal tissue overlap with those obtained from modera tely differentiated tumors, the degree of vascularization is not quali fied to serve as a prognostic factor in renal cell carcinomas. The com parison and interpretation of existing studies, however, is rendered m ore difficult as a result of the lack of standardized methods for the quantitative assessment of neoangiogenesis.