During the past 4 years, regional chemotherapy has been employed in the M. D. Anderson Hospital primarily as a medium of research in cancer, and secondarily for therapeutic purposes. At present, the 2 methods of administration consist of (1) perfusion with the use of the heart-lung machine, as suggested by Klopp5,6 and developed by Creech,2,3 and (2) continuous intra-arterial infusion, based upon the original work of Klopp5,6 and Bierman1 and their co-workers, and developed by Sullivan.14 As of Dec. 1, 1961, 265 perfusions had been performed for 209 patients, and 54 infusions for 48 patients. In the conviction that major "breakthroughs" in cancer research can best be achieved by cooperation between clinicians and investigators in the basic sciences, our approach has been a multidisciplinal one, in which surgeons, radiotherapists, pathologists, biochemists, biologists, and physicists have worked together. Herein will be presented some of the investigative