1. Cancer Prevention Basic Research Project; National Cancer Center Research Institute; 1-1 Tsukiji 5-chome; Chuo-ku; Tokyo 104-0045; Japan
2. Department of Public Health; Kyoto Pharmaceutical University; 5 Nakauchicho; Misasagi; Yamashina-ku, Kyoto 607-8414; Japan
3. Laboratory of Food Hygiene; Graduate School of Food and Nutritional Sciences; University of Shizuoka; 52-1 Yada; Suruga-ku; Shizuoka 422-8526; Japan