[Genetically high risk group for cancer associated with DNA repair deficiency].

Since the discovery of a DNA repair defect in xeroderma pigmentosum, which had been known as a hereditary cancer-prone disease, the presence of a genetically high risk group for cancer has been clearly recognized. Clinical and cellular investigations on xeroderma pigmentosum patients in Japan in comparison with those carried out in the United States and Europe have revealed that the characteristics of Japanese patients are considerably different from those in other countries. Similar differences have been noted in other related diseases like Bloom's syndrome. These results suggested that each ethnic group might have unique features with regard to the genetic background of carcinogenesis. Our research over the last 10 years has always been in good collaboration with colleagues in the USA, Europe and Korea thanks to support from the Japan Society for the Promotion of Sciences and the US-Japan Cooperative Medical Science Program, which has enabled us to perform comparative experimental work in foreign countries and to standardize methods and evaluation criteria.