This book records the proceedings of the 5th International Symposium on cancer topics organised in collaboration with the Association for International Cancer Research, a cancer charity based in the United Kingdom. The Symposium was held at the Klinikum Steglitz, Free University of West Berlin, Germany, between 1 and 3 October 1987. The Organising and Scientific Committees are deeply grateful to the President of the Free University, Professor Heckelmann, for allowing us to meet in the Klinikum Steglitz and for the University's generous financial support. It was a special pleasure to have a positive and generous input from the West Berlin Senate. Their support was crucial in making the Symposium a scientific success. The Symposium received financial support from a number of sponsors, and we are indeed happy to acknowledge our gratitude to them: Behringwerke AG, Bert- hold AG, Boehringer Mannheim GmbH, the British Council, Deutsche Abbott GmbH, Deutsche Bank AG, Du Pont De Nemours GmbH, Knoll AG, Krewel- werke GmbH, Nunc GmbH, Schering AG, Schwarz GmbH and Varian GmbH. The Symposium was the most ambitious so far mounted by the Association for International Cancer Research. The organisation and planning were carried through by an Organising Committee including Professor J. Hammerstein, Profes- sor K. D. Asmus, Barbara Steiger and Renate Nigam. The Scientific Committee included Dr. D. C. H. McBrien, Professor T. Dormandy, Professor K. R. Rees, Pro- fessor M. U. Dianzani and Professor H. Esterbauer. We thank these colleagues very much for their dedication, hard work and expert input.