Variable expression of the forgotten oncogene E5 in HPV-positive oropharyngeal cancer

Sung Ho Um, Neil Mundi, John Yoo, David A. Palma, Kevin Fung, Danielle MacNeil, Bret Wehrli, Joe S. Mymryk, John W. Barrett, Anthony C. Nichols

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

Background: The role of the HPV E6/E7 oncogenes in head and neck squamous cell cancer (HNSCC) has been studied extensively, but the role of the viral E5 protein remains poorly understood. Studies in cervical cancer indicate that E5 increases epidermal growth factor receptor (EGFR) recycling to the cell surface and enhances growth factor signal transduction. Objective: This study was designed to examine the relationship between HPV E5, EGFR, and survival in HPV-positive HNSCC. Study design: A retrospective search of the London Health Sciences Centre pathology database was performed to identify oropharyngeal cancer samples. HPV E5 and EGFR expression was measured by reverse transcriptase real-time PCR. Results: The majority of oropharyngeal tumor samples (59/82, 72%) were HPV-16 positive. Among the HPV-positive tumors, highly variable E5 expression was detected from early polycistronic transcripts. Tumors with high E5 expression levels had significantly higher EGFR levels (p=0.03). High E5 levels were correlated with improved recurrence-free survival, but not overall survival (p=0.02 and 0.71, respectively), whereas high EGFR was strongly associated with decreased recurrence-free and overall survival (p<0.001 and 0.006 respectively). Multivariate analysis revealed E5 and EGFR to be the strongest predictors of recurrence-free survival (p<0.01). Conclusions: HPV E5-encoded transcripts are variably expressed in HPV-positive HNSCC and this is correlated with EGFR expression in HPV-positive OPC. However, E5 and EGFR independently predict recurrence-free survival in opposing manners. These findings require further validation to determine if E5 and EGFR are useful biomarkers to stratify treatment intensity for patients with HPV-positive HNSCC.

Original languageEnglish
Pages (from-to)94-100
Number of pages7
JournalJournal of Clinical Virology
Volume61
Issue number1
DOIs
StatePublished - Sep 2014
Externally publishedYes

Keywords

  • E5
  • EGFR
  • Human papillomavirus
  • Oropharyngeal cancer
  • Viral oncogene

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