p16INK4A overexpression is frequently detected in tumour-free tonsil tissue without association with HPV

Boris Klingenberg, Harriet C. Hafkamp, Annick Haesevoets, Johannes J. Manni, Pieter J. Slootweg, Soenke J. Weissenborn, Jens P. Klussmann, Ernst-Jan M. Speel*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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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 languageEnglish
Pages (from-to)957-967
JournalHistopathology
Volume56
Issue number7
DOIs
Publication statusPublished - Jun 2010

Keywords

  • crypt epithelium
  • human papillomavirus
  • immunostaining
  • normal tonsil
  • p16INK4A
  • polymerase chain reaction
  • tumour-free tonsil

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