1. Department of Forensic Dental Medicine and Institute for Frontier Oral Science, Kanagawa Dental College, 82 Inaoka-cho, Yokosuka, Kanagawa 238-8580, JP.
2. Laboratory of Experimental Animal Science, Saitama Cancer Center Research Institute, Saitama 362-0806, JP.
3. Department of Clinical Pathology, Saitama Cancer Center Research Institute, Saitama 362-0806, JP.
4. Department of Biology, Kanagawa Dental College, Yokosuka 238-8580, JP.