[1] Univ Coll London Hosp, Head & Neck Ctr, London, England
[2] UCL, Sch Med, Dept Surg, London W1N 8AA, England
[3] UCL Eastman Dent Inst, Unit Oral & Maxillofacial Surg, London, England
[4] Royal Free & Univ Coll Med Sch, Dept Oral Pathol, London WC1E 6BT, England
[5] Univ Munich, Dept Otolaryngol, Munich, Germany
[6] Univ London Imperial Coll Sci Technol & Med, Dept Pathol, London, England
[7] Hammersmith Hosp, London, England