I. ETIOLOGY PROGRAM AREA

SUMMARY OF ACTIVITIES

The year April 1, 1982, to March 31, 1983, is the fourth year of the second 5-year program of the U.S.-Japan Cooperative Cancer Research Program. The aim of the Etiology Program Area is to clarify the causes of human cancers and to determine the mechanisms of carcinogenesis. It has been envisaged that cancer prevention may be eventually achieved through progress in the science of cancer etiology.
Three seminars were held during this period, one in Japan and two in the United States. One seminar focused on multiple primary human cancers in terms of possible genetic involvement and of unusual human exposures to carcinogens. It was realized that clinicians should play an important role in finding clues to human cancer etiology. The remaining seminars focused on environmental factors. One seminar concerned the new etiologies of human lung cancer. Certainly, cigarette smoking is the most important and the most preventable risk factor for the disease, but many unresolved problems, such as passive smoking, the changing cell type distribution, and diesel emissions, were also discussed. The second seminar covered environmental carcinogens to which humans may be exposed in their daily lives. New mutagens, promoters, and carcinogens in food (especially nitroso compounds) were emphasized. The subjects selected for these three seminars, described in detail below, were both timely and appropriate.
Of the six scientists who came to the United States from Japan during this period as exchange scientists, three conducted collaborative research in the area of viral oncology and three conducted research in the area of chemical carcinogenesis. Although the time spent in the United States by these scientists was relatively short, careful planning of research areas and selection of experienced scientists for the collaborative research made the exchange mutually profitable.