The activity of topoisomerases is related to the grade and stage in human renal cell carcinoma.

Human renal cell carcinomas are quite resistant to chemotherapy. There are no good anticancer agents effective for this disease. Recently, many anticancer agents were found to act as topoisomerase inhibitors and this is closely correlated with their anticancer activity. To assess the efficacy of anticancer agents as topoisomerase inhibitors on renal cell carcinomas, we examined the activity of topoisomerase I and topoisomerase II in 60 primary human renal cell carcinomas using DNA relaxation or DNA decatenation. Significant topoisomerase I and topoisomerase II activities were observed in 39(65%) or 22(36.7%) cases respectively. Topoisomerase II positive cases were more frequent in higher grade cancers (p < 0.01). The topoisomerase I positive rate did not differ in all grades. Our results showed that human renal cell carcinomas had significant topoisomerase I or topoisomerase II activities that were targets for some topoisomerase inhibitors. Therefore these agents could be good candidates for the chemotherapy of human renal cell carcinomas.