A study of topoisomerase activity in human testicular cancers.

Topoisomerases are widely detected in rapidly proliferating cancer cells. Many anti-topoisomerase agents are utilized for cancer chemotherapy. Testicular cancers are highly chemotherapy sensitive, however, 10% of them are refractory to the standard regimen. To investigate the topoisomerase activities in human testicular neoplasms, we examined the activity of topoisomerase I (TopoI) and topoisomerase II (TopoII) in 29 testicular tumors. TopoI activity was observed irrespective of pathological types of the tumor (21/29). TopoII was detected in seminoma and teratocarcinoma (5/29). In our experience, seminoma was relatively sensitive to chemotherapy including anti-TopoII agents. Our results suggest that Topol inhibitors could be more effective against seminoma as well as the other types of testicular tumors.