Mucosal and skin HPV types in tumour-free tonsils and tonsillar tumours

 Martina Saláková, Eva Košľabová, Marek Grega, Jana Šmahelová, Jan Klozar, Ondřej Vencálek, Ruth Tachezy

Abstract:

Human papillomavirus (HPV) infection is associated with tonsillar cancer (TC) whose incidence in man is increasing. Tonsillar tumours are not ordinarily preceded by clinically apparent precancerous lesions, and no markers of the early stage disease are available. Therefore, we evaluated the presence of an active HPV infection also in tumour-free tonsillar tissues. Formalin-fixed paraffin-embedded (FFPE) tonsillar specimens from 114 patients with TC and 114 age and gender matched controls were screened for the presence of HPV DNA, expression of HR-HPV E6 mRNA, and p16 overexpression. HPV DNA was identified in 3.5% of tumour-free tissues, HR-HPV16 and 58 and LR-HPV111 and 17 detected in a single sample. No HR HPV E6 mRNA and p16 overexpression was detected. The prevalence of HPV DNA in TC was 69.3%, with HPV16 the most common (94.9%). Eighty-four percent of HPV16 positive tumours expressed HR HPV E6 mRNA while no E6 mRNA was present in samples positive for HPV52 and 58. The overexpression of p16 correlated well with HPV DNA in TC, but in tumour-free tonsils, no overexpression of p16 was detected. Our data provides further evidence of the etiological role of HPV16 in TC. In tumour-free tissue, the presence of HR-HPVs was rare and silent, as evidenced by direct and indirect markers.