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Epigenetic inactivation of RASSF1A in head and neck cancer

Seung Myung Dong1, Dong-Il Sun, Nicole E Benoit

  • 1Department of Otolaryngology-Head and Neck Surgery, Head and Neck Cancer Research Division, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2196, USA. dsidrans@jhmi.edu

Clinical Cancer Research : an Official Journal of the American Association for Cancer Research
|September 25, 2003
PubMed
Abstract

Insights

The RASSF1A gene, a tumor suppressor, is inactivated in some head and neck cancers. Promoter methylation and HPV infection show an inverse correlation, suggesting they impact the same cancer pathway.

Area of Science:

  • Oncology
  • Molecular Biology
  • Genetics

Background:

  • RASSF1A is a candidate tumor suppressor gene.
  • RASSF1A inactivation is observed in various cancers, including lung cancer.
  • Its role in head and neck squamous cell carcinoma (HNSCC) requires investigation.

Purpose of the Study:

  • To investigate the inactivation status of RASSF1A in HNSCC.
  • To determine the correlation between RASSF1A alterations and human papillomavirus (HPV) infection in HNSCC.

Main Methods:

  • Analysis of RASSF1A promoter hypermethylation using methylation-specific PCR.
  • Detection of RASSF1A point mutations via direct sequencing.
  • Assessment of HPV DNA presence in HNSCC samples.
  • Treatment of cell lines with 5-aza-2-deoxycytidine to evaluate RASSF1A re-expression.

Main Results:

  • RASSF1A promoter methylation was found in 42.9% of cell lines and 15% of primary HNSCC tumors.
  • Point mutations in RASSF1A were identified in one cell line and one primary tumor.
  • RASSF1A re-expression and demethylation occurred after 5-aza-2-deoxycytidine treatment.
  • HPV DNA was detected in 34.7% of primary HNSCC, with a significant inverse correlation to RASSF1A promoter methylation (P = 0.038).

Conclusions:

  • RASSF1A is inactivated in a subset of HNSCC through promoter methylation.
  • An inverse correlation exists between RASSF1A promoter methylation and HPV infection.
  • These findings suggest that RASSF1A methylation and HPV infection converge on common tumorigenic pathways in HNSCC.

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