[1] Univ Helsinki, Dept Pathol, Haartmaninkatu 3,POB 21, FIN-00014 Helsinki, Finland
[2] Univ Helsinki, Res Program Syst Oncol, Fac Med, Helsinki, Finland
[3] Univ Turku, Inst Biomed, Pathol, Turku, Finland
[4] Univ Misurata, Fac Dent, Misurata, Libya
[5] Univ Helsinki, Dept Otorhinolaryngol Head & Neck Surg, Helsinki, Finland
[6] Helsinki Univ Hosp, Helsinki, Finland
[7] Karolinska Inst, Dept Clin Sci Intervent & Technol, Div Ear Nose & Throat Dis, Stockholm, Sweden
[8] Karolinska Hosp, Stockholm, Sweden