We propose to organize the `Second Conference on DNA Topoisomerases in Cancer Chemotherapy', in October 17-19, 1988, at the New York University Medical Center. The preparation and organization of the Conference will include: 1. Dissemination of information regarding the conference by mail and by advertisement or announcements in scientific journals. 2. Organization of the actual conference which will be held as a three day meeting with four plenary sessions of slide presentations, and with two poster sessions. Each slide session will include invited speakers, most of them leading experts in the field, as well as presenters of selected proffered papers. There are four topics of plenary sessions: (i) Genetic studies of topoisomerases; (ii) Topoisomerase I-directed drugs; (iii) Inhibitors of topoisomerase II and mechanism of their action; and (iv) Topoisomerase-related drug resistance. 3. Publication of conference lectures as full-size articles. An attempt will be made to publish the proceedings as a separate issue of the NCI Monographs. The goals of the conference are three-fold: (i) To broaden and update information concerning biology of DNA topoisomerases and the mechanism of inhibition by chemotherapeutic agents; (ii) Once again, to bring together cancer researchers and clinicians interested in the topic, accelerate the transfer of information from basic science into the drug development and clinical studies; and (iii) To assess present advances and discuss future directions in this field. A special effort will be made to include scientists not only from the United States and Canada, but also from abroad.