1. Department of Pathology II, Kansai Medical University, 2-5-1 Shin-machi, Hirakata, Osaka 573-1010, Japan
2. Division of Diagnostic Cytopathology and Histopathology, Kansai Medical University Takii Hospital, Fumizono 10-15, Moriguchi, Osaka 570-8507, Japan
3. Cellular & Molecular Pathology Branch, National Institute of Environmental Health Sciences, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA.