title: DNA methylation analysis of cancer-related genes in oral epithelial cells of healthy smokers.
abstract: OBJECTIVE
  The aim of this study was to investigate the smoking habit influence on DNA methylation status in the promoters of the cancer related-genes MLH1, hTERT and TP53 in oral epithelial cells of healthy subjects.
  
  
  METHODS
  DNA methylation analysis was performed using methylation-sensitive restriction enzymes (MSRE) in oral epithelial cells from non-smokers, smokers and ex-smokers.
  
  
  RESULTS
  The investigated CpG dinucleotides located at HhaI and HpaII sites in the MLH1 gene promoter were observed to be fully methylated in the majority of DNA samples from the smoker group and statistical differences were found between non-smokers and smokers and between smokers and ex-smokers (p<0.05). The same was observed in the hTERT gene promoter at HhaI sites (p<0.05) and for HpaII sites the unmethylated condition was more frequent in smokers in comparison to non-smokers (p<0.05). For TP53, no differences were found among groups (p>0.05), with the fully methylated condition found to be a common event in healthy oral epithelial cells.
  
  
  CONCLUSIONS
  We conclude that smoking may induce changes in DNA methylation status in cancer-related genes of oral epithelial cells and that the cessation of smoking is capable of reversing this process. Based on our data, we suggest that DNA methylation status of the hTERT and MLH1 gene promoters are promising markers for screening a set of smoking-related alterations in oral cells.
authors: Programa de Pós Graduação em Odontologia, Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, PB, Brazil.
authors: Sabrina Rocha Luna
authors: SR
authors: De Oliveira
authors: Departamento de Biologia Molecular, Centro de Ciências Exatas e da Natureza, Universidade Federal da Paraíba, João Pessoa, PB, Brazil.
authors: Isabelle Cristina Borba
authors: IC
authors: Da Silva
authors: Departamento de Morfologia, Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, PB, Brazil.
authors: Bruno Augusto Linhares Almeida
authors: BA
authors: Mariz
authors: Departamento de Morfologia, Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, PB, Brazil.
authors: Ana Maria Barros Chaves
authors: AM
authors: Pereira
authors: Programa de Pós Graduação em Odontologia, Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, PB, Brazil; Departamento de Biologia Molecular, Centro de Ciências Exatas e da Natureza, Universidade Federal da Paraíba, João Pessoa, PB, Brazil. Electronic address: naila_francis@yahoo.com.br.
authors: Naila Francis Paulo
authors: NF
authors: De Oliveira
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics*; D014408:Biomarkers, Tumor / Q000032:analysis*; D019175:DNA Methylation; D004847:Epithelial Cells / Q000473:pathology*; D005260:Female; D005819:Genetic Markers; D006801:Humans; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000166:cytology* / Q000473:pathology; D009062:Mouth Neoplasms / Q000175:diagnosis* / Q000235:genetics*; D000070957:MutL Protein Homolog 1; D009687:Nuclear Proteins / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D012907:Smoking; D016159:Tumor Suppressor Protein p53 / Q000235:genetics*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D014408:Biomarkers, Tumor; D005819:Genetic Markers; C501486:MLH1 protein, human; D009687:Nuclear Proteins; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D000070957:MutL Protein Homolog 1
keywords: DNA methylation; Epigenetic; MLH1; Oral cells; Smoking; Telomerase