The data, the information, and even the overarching knowledge necessary for risk assessments of economically important environmental carcinogens come, for the most part, from the applied biological disciplines, e. g. , toxicology, epidemiology, biostatistics, etc. The more fundamental biological disciplines, e. g. , biochemistry, cell biology, molecular biology, molecular genetics of cancer, etc. , have enormous but unrealized potential to improve current cancer risk assessment methods. The objective of this advanced research workshop ARW was to advance the state of the art of cancer risk assessment methods by identifying potential short and long term contributions to such methods from the more fundamental disciplines. Attention was paid to short and long term contributions from research advances in the biochemistry and physiology of oncogenes (oncogenes research) and in the construction and utilization of transgenic animals (transgenics research). In the last 20 years, researchers in the fundamental biological disciplines, i. e. , biochemists, geneticists, molecular and cell biologists, etc. , have, inter alia, advanced spectacularly our understanding of the nature of neoplastic diseases. Their phenomenal progress is the combined result of both advances and refinements of the techniques available to them and of new fundamental discoveries. Among the latter the most significant are the discoveries of oncogenes and of the feasibility of creating transgenic animals, i. e. , of transferring well defined and expressible genes from the cells of one species of organisms to the embryonic cells of another.