It is now apparent that several fields of investigation are converging upon each other as the goal of finding a practical way to prevent cancer is pursued. The present monograph represents the efforts of an interdisciplinary ESO Task Force that was convened to assess interactions of peptide growth factors and steroid-like molecules in the prevention of cancer. Each of the participants in the Task Force represents a differentscientific discipline, and the monogrph is intended to be a synthesis of their different approaches to the common problem of cancer prevention. It is hoped that the reader will find this monograph to be of use in the evaluation