title: Promoter methylation and loss of p16(INK4a)  gene expression in head and neck cancer.
abstract: BACKGROUND
  Silencing of tumor suppressor genes plays a vital role in head and neck carcinogenesis. In this study we aimed to evaluate aberrant p16(INK4a) gene promoter methylation in patients with head and neck cancer.
  
  
  METHODS
  Methylation of the gene was investigated by bisulfite modification/methylation-specific polymerase chain reaction and gene expression levels were analyzed by quantitative reverse transcription-polymerase chain reaction in tumors and matched normal tissue samples from Turkish patients with head and neck cancer.
  
  
  RESULTS
  The promoter region of the p16(INK4a) gene was methylated in 67.5% and 28.6% of the primary tumors and the corresponding normal tissue, respectively. This difference was highly significant. In concordance, p16(INK4a) gene expression was downregulated in 67.5% of the tumor samples. Methylation and the absence of expression in the tumors were observed in 48% of the patients.
  
  
  CONCLUSIONS
  Our data indicate that methylation of the p16(INK4a) gene is a frequent event in primary head and neck cancer and that it plays a major role in the silencing of p16(INK4a) gene expression during tumor development.
authors: Department of Basic Oncology, Oncology Institute, Istanbul University, Istanbul, Turkey.
authors: Semra
authors: S
authors: Demokan
authors: Alice
authors: A
authors: Chuang
authors: Yusufhan
authors: Y
authors: Suoğlu
authors: Murat
authors: M
authors: Ulusan
authors: Zubeyde
authors: Z
authors: Yalnız
authors: Joseph A
authors: JA
authors: Califano
authors: Nejat
authors: N
authors: Dalay
mesh_terms: D000328:Adult; D000368:Aged; D002294:Carcinoma, Squamous Cell / Q000235:genetics* / Q000473:pathology; D016001:Confidence Intervals; D019175:DNA Methylation / Q000235:genetics; D004273:DNA, Neoplasm / Q000235:genetics; D015536:Down-Regulation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D019942:Genes, p16; D005823:Genetics; D006258:Head and Neck Neoplasms / Q000235:genetics* / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D012494:Sampling Studies; D000077195:Squamous Cell Carcinoma of Head and Neck
chemical_list: D004273:DNA, Neoplasm