title: Methylation and mutation analysis of p16 gene in gastric cancer.
abstract: OBJECTIVE
  To study methylation, frequencies of homozygous deletion and mutation of p16 gene in gastric carcinoma.
  
  
  METHODS
  The methylation pattern in exon 1 and exon 2 of p16 gene was studied with polymerase chain reaction (PCR), using methylation sensitive restriction endonuclease HpaII and methylation insensitive restriction endonuclease MspI. PCR technique was used to detect homozygous deletions of exon 1 and exon 2 of p16 gene and single strand conformation polymorphism (SSCP) technique was used to detect the mutation of the gene.
  
  
  RESULTS
  Hypermethylation changes in exon 1 and exon 2 of p16 gene were observed in 25 % and 45 % of 20 gastric cancer tissues, respectively, while no methylation abnormality was found in normal tissues. The homozygous deletion frequency of exon 1 and exon 2 of p16 gene in 20 gastric cancer tissues was 20 % and 10 %, respectively. No mutation was found in exon 1 of p16 gene, while abnormal single strands were found in 2 (10 %) cases in exon 2 as detected by SSCP.
  
  
  CONCLUSIONS
  The results suggest that hypermethylation and abnormality of p16 gene may play a key role in the progress of gastric cancer. Hypermethylation of exon 2 of p16 gene may have effects on the carcinogenesis of gastric mucosa and may be a later event.
authors.affiliation: Molecular Cell Biology Research Center, Medical College of Zhengzhou University; 40 Daxue Road, Zhengzhou 450052, Henan Province, China. qxz53@zzu.edu.cn
authors.forename: Yi
authors.initials: Y
authors.lastname: Ding
authors.forename: Xiao-Ping
authors.initials: XP
authors.lastname: Le
authors.forename: Qin-Xian
authors.initials: QX
authors.lastname: Zhang
authors.forename: Peng
authors.initials: P
authors.lastname: Du
mesh_terms: D019175:DNA Methylation; D004252:DNA Mutational Analysis; D017353:Gene Deletion; D019942:Genes, p16; D006801:Humans; D009154:Mutation; D013274:Stomach Neoplasms / Q000235:genetics*