1. Joint Graduate School of Veterinary Medicine, Kagoshima University, Korimoto, Kagoshima, Japan
2. Veterinary Teaching Hospital, Joint Faculty of Veterinary Medicine, Kagoshima University, Korimoto, Kagoshima, Kagoshima, Japan
3. Department of Human Oncology, University of WI School of Medicine and Public Health, Madison, WI, USA
4. Laboratory of Veterinary Surgery, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, Japan