1. Department of Surgical Pathology; Sapporo Medical University; School of Medicine; South 1, West 16, Chuo-ku, Sapporo Hokkaido 060-8543 Japan
2. Department of Pathology; Kushiro Red Cross Hospital; Kushiro Hokkaido 085-8512 Japan
3. Department of Medicine; Kushiro Red Cross Hospital; Kushiro Hokkaido 085-8512 Japan