EVALUATION OF MICROVESSEL DENSITY BY COMPUTERIZED IMAGE-ANALYSIS IN HUMAN RENAL-CELL CARCINOMA - CORRELATION TO PT CATEGORY, NUCLEAR GRADE,PROLIFERATIVE ACTIVITY AND OCCURRENCE OF METASTASIS

A high microvessel density is suspected to Favour tumour progression a nd the occurrence of metastasis. To elucidate the significance of abun dant vessels for the behaviour of human renal carcinomas, the microves sel density of 110 renal cell carcinomas was correlated to pT category , nuclear grade, proliferative activity, occurrence of metastasis and relapse-free survival interval. The microvessels were quantified using CD31 immunostaining of endothelial cells and computer-aided image ana lysis. The rules for reproducible microvessel counting, as defined by Weidner, were strictly observed. A statistically significant relations hip between the microvessel density and nuclear grade, proliferative a ctivity, occurrence of metastasis and relapse-free survival was found; only for tumour size could no such relation be seen. Perplexingly, th ere is a diminution of microvessel density in association with increas ing nuclear grade, proliferative activity, relapse-free survival inter val and frequency of metastasis. This finding is contradictory to the hypothesis that an increasing microvessel density indicates a worsenin g prognosis.