PROGRAM AREA REPORTS

URINARY BLADDER CANCER PROGRAM

Studies on carcinogenesis are not only important in the United States, but equally important to other industrial nations due to greater exposure to environmental and chemical carcinogens. The Japanese scientists have long been interested in chemical carcinogenesis and have been investigating pure substances as causative agents. Studies on new techniques and insights in research have naturally led to cooperative studies.
The Urinary Bladder Cancer Program Area has initiated collaborative studies on chemical carcinogenesis and related areas and has brought to focus the increasing incidence of bladder cancer in both countries. The incidence in Japan has shown a strikingly sharp upward slope.
At the “Joint Conference on Experimental Models for Bladder Cancer” held in Hawaii in December 1975, the current status of methods utilized to induce urinary bladder cancer in experimental animals was discussed and similarities and differences exhibited by these models and human urinary bladder cancer were described. Fruitful discussions were also held on chemical carcinogens, animal species, histogenesis, and mechanism of bladder carcinogenesis.
The Japanese scientists introduced a proximate form of BBN and an American scientist presented a study on urinary bladder carcinogenesis by 2-acetylaminofluorene.
There were three major accomplishments during 1976 and 1977. First, an interdisciplinary meeting on “The Etiology of Bladder Cancer” was held in Kyoto, September 1976, attended by clinicians, epidemiologists, pathologists, and molecular biologists. The subject of carcinogens in bracken fern as an etiologic factor in animal and human bladder cancer was one of the main topics for intensive and extensive discussion. A considerable amount of research on bracken fern is being conducted in Japan and several other countries. Other areas discussed were the genetic factors in bladder cancer and the relation of tryptophane metabolism and bladder cancer. The histopathology on over 500 human cases each in Japan and the U.S. were compared by a Japanese scientist visiting the United States. Since no differences in histopathological types were perceived, the likelihood of successful collaborative clinical studies was discussed and planned.
The second achievement was the long-term exchange of Dr. S.M. Cohen to the laboratory of Professor N. Ito at the Nagoya City University Medical School. During Dr. Cohen’s one-year stay in Japan, the extensive collaborative studies being carried out in the field of clinical pathology yielded nine papers such as reversible papillary hyperplasia of the rat urinary bladder and effect of azathioprine on rat urinary bladder carcinogenesis, in addition to eight abstracts. Productive exchanges of scientists from Japan to U.S. laboratories continued.
The third major area of activity was the initiation of publications representing collaborative studies. These papers document the degree to which collaborative efforts are occurring.
As the consequence of the past accomplishments and program planning, a strong base of productive and collaborative activities of laboratory-based research has been fostered for an enhanced understanding of the initiation and pathogenesis of uroepithelial neoplasia. Epidemiological studies designed to identify high-risk population groups have been established.
Clinical studies are in their early phases of development in both the U.S. and Japan and until each country can separately consolidate their activities it would be premature to attempt bilateral activities. However, increasing collaborative activities in clinical research are being planned in view of the great interest in bladder cancer in both countries. Japanese scientists will continue to be active participants in the National Bladder Cancer Program sponsored by the National Cancer Institute.