Comprehensive analysis of HPV16 integration in OSCC reveals no significant impact of physical status on viral oncogene and virally disrupted human gene expression

PLoS One. 2014 Feb 24;9(2):e88718. doi: 10.1371/journal.pone.0088718. eCollection 2014.

Abstract

Infection with high-risk human papillomavirus (HPV) type 16 is an independent risk factor for the development of oropharyngeal squamous cell carcinomas (OSCC). However, it is unclear whether viral integration is an essential hallmark in the carcinogenic process of OSCC and whether HPV integration correlates with the level of viral gene transcription and influences the expression of disrupted host genes. We analyzed 75 patients with OSCC. HPV16-positivity was proven by p16(INK4A) immunohistochemistry, PCR and FISH. Viral integration was examined using DIPS- as well as APOT-PCR. Viral E2, E6 and E7 gene expression levels were quantified by quantitative reverse transcriptase (RT-q)PCR. Expression levels of 7 human genes disrupted by the virus were extracted from mRNA expression profiling data of 32 OSCCs. Viral copy numbers were assessed by qPCR in 73 tumors. We identified 37 HPV16-human fusion products indicating viral integration in 29 (39%) OSCC. In the remaining tumors (61%) only episome-derived PCR products were detected. When comparing OSCC with or without an integration-derived fusion product, we did not find significant differences in the mean RNA expression of viral genes E2, E6 and E7 or the viral copy numbers per cell, nor did the RNA expression of the HPV-disrupted genes differ from either group of OSCC. In conclusion, our data do not support the hypothesis that integration affects the levels of viral and/or HPV-disrupted human gene transcripts. Thus constitutive, rather than a high level, of expression of oncogene transcripts appears to be required in HPV-related OSCC.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Carcinoma, Squamous Cell / genetics
  • DNA, Viral / genetics
  • Female
  • Gene Expression / genetics*
  • Genes, Viral / genetics
  • Human papillomavirus 16 / genetics*
  • Humans
  • Male
  • Middle Aged
  • Oncogene Proteins, Viral / genetics*
  • Oropharyngeal Neoplasms / genetics*
  • Papillomavirus E7 Proteins / genetics
  • Papillomavirus Infections / genetics*
  • RNA, Messenger / genetics
  • RNA, Viral / genetics
  • Virus Integration / genetics*

Substances

  • DNA, Viral
  • Oncogene Proteins, Viral
  • Papillomavirus E7 Proteins
  • RNA, Messenger
  • RNA, Viral

Grants and funding

This study was supported by the Koeln Fortune Program, Faculty of Medicine, University of Cologne, Cologne, Germany (Grant number 40/2010 to CUH) and the Jean Uhrmacher Foundation, Cologne, Germany. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.