1. Department of Oral and Maxillofacial, Okazaki City Hospital, Okazaki, Japan
2. Head and Neck Service, Tata Memorial Hospital, Mumbai, India
3. Head and Neck Service, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
4. Early Detection and Prevention Section (EDP), International Agency for Research on Cancer, 69372 Lyon, France