Hypermethylation of the p16 gene in normal oral mucosa of smokers
The oral cavity is the sixth most common anatomical localization of head and neck carcinoma in men. Detection of oral carcinomas in the early asymptomatic stages improves cure rates and the quality of life. Tobacco smoking and alcohol drinking are the most important known risk factors
for the development of head and neck tumors, suggesting that the exposure to these risk factors may increase the predisposition for genetic and epigenetic alterations, such as DNA methylation. The presence of methylated CpG islands in the promoter region of human genes can suppress their expression
due to the presence of 5-methylcytosine that interferes with the binding of transcription factors or other DNA-binding proteins repressing transcription activity. Hypermethylation leading to the inactivation of some tumor suppressor genes, such as p16, has been pointed out as an initial event
in head and neck cancer. Our aim was to evaluate an early diagnostic method of oral pre-cancerous lesions through the analysis of methylation of the p16 gene. DNA samples from normal oral mucosa and posterior tongue border from 258 smokers, without oral cancer, were investigated for the occurrence
of p16 promoter hypermethylation. The methylation status of the p16 gene was analyzed using MS-PCR (methylation-sensitive restriction enzymes and PCR amplification), MSP (Methylation-specific PCR) or direct DNA sequence of bisulfite modified DNA. Hyper-methylation was detected in 9.7% (25/258)
of the cases analyzed. These findings provide further evidence that epigenetic alteration, leading to the inactivation of the p16 tumor suppressor gene is an early event that might confer cell growth advantages contributing to the tumorigenic process. Thus, the detection of abnormal p16 methylation
pattern may be a valuable tool for early oral cancer detection.
Document Type: Research Article
Affiliations: Disciplina de Semiologia, Departamento de Estomatologia, Faculdade de Odontologia da Universidade de São Paulo, CEP-05508-900, São Paulo, SP, Brazil
Publication date: 01 November 2004
- The International Journal of Molecular Medicine is a monthly, peer-reviewed journal devoted to the publication of high quality studies related to the molecular mechanisms of human disease. The journal welcomes research on all aspects of molecular and clinical research, ranging from biochemistry to immunology, pathology, genetics, human genomics, microbiology, molecular pathogenesis, molecular cardiology, molecular surgery and molecular psychology.
The International Journal of Molecular Medicine aims to provide an insight for researchers within the community in regard to developing molecular tools and identifying molecular targets for the diagnosis and treatment of a diverse number of human diseases. - Editorial Board
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