[1] Univ Freiburg, Dept Otorhinolaryngol Head & Neck Surg, D-79106 Freiburg, Germany
[2] Vrije Univ Amsterdam Med Ctr, Dept Otolaryngol Head & Neck Surg, Amsterdam, Netherlands
[3] Univ Freiburg, Dept Nephrol & Gen Med, D-79106 Freiburg, Germany
[4] PAL Dordrecht, Pathol Lab, Dordrecht, Netherlands
[5] Hosp Univ Cent Asturias, Dept Otolaryngol, Oviedo, Spain
[6] Inst Univ Oncol Principado Asturias, Oviedo, Spain
[7] Radboud Univ Nijmegen, Dept Otolaryngol Head & Neck Surg, Med Ctr, NL-6525 ED Nijmegen, Netherlands
[8] Guthrie Hlth Syst, Dept Otolaryngol Head & Neck Surg, Sayre, PA USA
[9] Univ Udine, ENT Clin, I-33100 Udine, Italy