ETIOLOGY PROGRAM AREA

SUMMARY OF ACTIVITIES

The year April 1, 1989 to March 31, 1990 is the first year of the fourth 5-year program of the U.S.-Japan Cooperative Cancer Research Program. The objective 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 achieved eventually through progress in the science of cancer etiology.
Four seminars were held during this period, three in the United States and one in Japan. The first seminar, “Human Cancer Genes: Growth Factor and Tumor Suppressor Genes,” focused on the genes and molecular mechanisms involved in the conversion of normal cells to neoplastic cells. The second seminar, “Recent Advances in Research on Heterocyclic Amines,” dealt with the heterocyclic amines found in cooked meat, fowl, and fish which have been found to be mutagenic and several are carcinogenic in animal experiments. These compounds collectively are referred to as heterocyclic amines and have a free amino group and an arylnitrogen. The third seminar, “Multifactorial Etiology and Multistep Development of Hepatocellular Carcinoma,” presented recent findings and views on the multifactorial etiology of hepatocellular carcinoma and the stepwise development of the disease with emphasis on aflatoxin B₁ and hepatitis B virus as etiological factors. The fourth seminar, “Molecular Mechanisms of Initiation, Promotion, and Progression,” was dedicated to the late Professor Takeo Kakunaga, and the following day the Takeo Kakunaga Memorial Lectures were presented. The seminar focused on recent information and ideas on a molecular level concerning initiation, promotion and progression of cancer.
Five scientists from Japan participated in the exchange programs in etiology research, which has as its mission to provide a fundamental basis for understanding cancer causation that, in turn, would help in identifying effective means for preventing or modulating this process.
During this reporting period, the following compounds were shipped to the United States from Japan: 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxalin and 2-amino-3,8-dimethylimidazo[4,5-f] quinoxaline.