[1] Univ Helsinki, Dept Pathol, POB 21, FI-00014 Helsinki, Finland
[2] Helsinki Univ Hosp, POB 21, FI-00014 Helsinki, Finland
[3] Univ Helsinki, Dept Otorhinolaryngol Head & Neck Surg, POB 263, FI-00029 Hus Helsinki, Finland
[4] Helsinki Univ Hosp, POB 263, FI-00029 Hus Helsinki, Finland
[5] Univ Helsinki, Fac Med, Res Program Syst Oncol, POB 63, FI-00014 Helsinki, Finland
[6] Univ Helsinki, Dept Clin Chem, POB 63, FI-00014 Helsinki, Finland
[7] Helsinki Univ Hosp, POB 63, FI-00014 Helsinki, Finland
[8] Univ Helsinki, Res Programs Unit, Translat Canc Med, POB 63, FI-00014 Helsinki, Finland
[9] Univ Helsinki, Dept Surg, POB 440, FI-00029 Helsinki, Finland
[10] Helsinki Univ Hosp, POB 440, FI-00029 Helsinki, Finland
[11] Turku Univ Hosp, Dept Pathol, Kiinamyllynkatu 10, Turku 20520, Finland
[12] Karolinska Inst, Div Ear Nose & Throat Dis, Dept Clin Sci Intervent & Technol, SE-17176 Stockholm, Sweden
[13] Karolinska Hosp, SE-17176 Stockholm, Sweden
[14] Univ Turku, Dept Oral Pathol & Oral Radiol, Lemminkaisenkatu 2, Turku 20520, Finland