Abstract
Aims: Oncogenic human papillomavirus (HPV) type 16 has been strongly associated with tonsillar squamous cell carcinoma (TSCC) and appears to be of prognostic significance. Because HPV+ TSCC also accumulates p16INK4A, this cyclin-dependent kinase inhibitor has been proposed as a potential biomarker for HPV in clinical diagnosis. The aim of this study was to determine the prevalence of HPV in tumour-free tonsillar tissue and the value of p16INK4A overexpression in predicting its presence. Methods and results: p16INK4A overexpression was detected by immunohistochemistry in tissue sections of tumour-free tonsils of 262 patients. They were treated for non-oncological reasons (snoring or chronic/recurrent tonsillitis) consisting of tonsillectomy. Genomic DNA isolated from these tissues was subjected to HPV-specific polymerase chain reaction (PCR) analysis. p16INK4A immunoreactivity was detected in 28% of samples in both crypt epithelium (49/177) and lymphoid germinal centres (52/187), which correlated with each other (P <0.0001). No reactivity was observed in superficial squamous cell epithelium. HPV16 and 18 were detected by PCR analysis in 2/195 cases (1%), which, however, were negative on fluorescence in situ hybridization analysis and discrepant on p16INK4A immunostaining. Conclusions: No proof was found for the presence of HPV in tumour-free tonsil tissue, despite increased p16INK4A expression in a quarter of tonsil cases. Other mechanisms than HPV infection are therefore implicated in p16INK4A up-regulation.
Original language | English |
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Pages (from-to) | 957-967 |
Journal | Histopathology |
Volume | 56 |
Issue number | 7 |
DOIs | |
Publication status | Published - Jun 2010 |
Keywords
- crypt epithelium
- human papillomavirus
- immunostaining
- normal tonsil
- p16INK4A
- polymerase chain reaction
- tumour-free tonsil