Double demonstration of oncogenic high risk human papilloma virus DNA and HPV-E7 protein in oral cancers

Int J Immunopathol Pharmacol. 2011 Apr-Jun;24(2 Suppl):95-101. doi: 10.1177/03946320110240S217.

Abstract

Oncogenic HPVs are necessarily involved in cervical cancer but their role in oral carcinogenesis is debated. To detect HPV in oral cancer, 38 cases of formalin fixed-paraffin embedded OSCC were studied by both DNA genotyping (MY09/11 L1 consensus primers in combination with GP5-GP6 primer pair followed by sequencing) and immunohistochemistry (monoclonal Abs against capsid protein and HPV-E7 protein, K1H8 DAKO and clone 8C9 INVITROGEN, respectively). HPV-16 tonsil cancer was used as positive control. The overall prevalence of HPV infection in OSCCs was 10.5%. Amplification of DNA samples showed single HPV DNA infection in 3 cases (HPV16; HPV53; HPV70) and double infection in one case of cheek cancer (HPV31/HPV44). The overall HR-HPV prevalence was 7.5%. E-7 antigen was immunohistochemically detected in all HPV-positive cases. HPV+ OSCC cases showed an overall better outcome than HPV negative oral cancers, as evaluated by Kaplan-Meier curves. HPVs exert their oncogenic role after DNA integration, gene expression of E5, E6 and E7 loci and p53/pRb host proteins suppression. This study showed that HPV-E7 protein inactivating pRb is expressed in oral cancer cells infected by oncogenic HPV other than classical HR-HPV-16/18. Interestingly HPV-70, considered a low risk virus with no definite collocation in oncogenic type category, gives rise to the expression of HPV-E7 protein and inactivate pRb in oral cancer. HPV-70, as proved in current literature, is able to inactivates also p53 protein, promoting cell immortalization. HPV-53, classified as a possible high risk virus, expresses E7 protein in OSCC, contributing to oral carcinogenesis. We have identified among OSCCs, a subgroup characterized by HPV infection (10.5%). Finally, we have proved the oncogenic potential of some HPV virus types, not well known in literature.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Carcinoma, Squamous Cell / epidemiology
  • Carcinoma, Squamous Cell / metabolism
  • Carcinoma, Squamous Cell / pathology
  • Carcinoma, Squamous Cell / virology*
  • DNA, Viral / analysis
  • Female
  • Humans
  • Male
  • Middle Aged
  • Mouth Neoplasms / epidemiology
  • Mouth Neoplasms / metabolism
  • Mouth Neoplasms / pathology
  • Mouth Neoplasms / virology*
  • Neoplasm Staging
  • Papillomaviridae / genetics*
  • Papillomaviridae / metabolism
  • Papillomavirus E7 Proteins / genetics
  • Papillomavirus E7 Proteins / metabolism
  • Papillomavirus Infections / epidemiology
  • Papillomavirus Infections / genetics
  • Papillomavirus Infections / virology*

Substances

  • DNA, Viral
  • Papillomavirus E7 Proteins