title: Quantitative assessment of gene methylation and their impact on clinical outcome in gastric cancer.
abstract: BACKGROUND
  Promoter methylation is an alternative mechanism of gene silencing in human tumorigenesis. Although a number of methylated genes have been found in gastric cancer, useful methylation markers for early diagnosis and prognostic evaluation of this cancer remain largely unknown.
  
  
  METHODS
  Using quantitative methylation-specific PCR (Q-MSP), we examined promoter methylation of 6 genes, including CALCA, DAPK1, RARbeta, RASSF1A, TIMP3, and PAX6, and explored their association with clinical outcome in gastric cancer.
  
  
  RESULTS
  We found that most of the genes investigated in the present study had significantly higher methylation level in tumor tissues than normal gastric tissues, including CALCA, RARbeta, RASSF1A, TIMP3, and PAX6. With more focus on specificity compared to sensitivity, all genes were hypermethylated in gastric cancer, ranging from 12.8% to 36.9%. Methylation of TIMP3 and PAX6 was strongly associated with differentiation and lymph node metastasis, respectively. Importantly, most of gene methylation, except for DAPK1, was closely associated with poor survival in gastric cancer.
  
  
  CONCLUSIONS
  We found that a panel of genes was specifically methylated in gastric cancer, and demonstrated the effect of promoter methylation of some genes on clinical outcome in gastric cancer, indicating these methylated genes may be useful biomarkers for prognostic evaluation in this cancer.
authors.affiliation: Department of Surgery, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an, People's Republic of China.
authors.forename: Demao
authors.initials: D
authors.lastname: Yao
authors.forename: Jing
authors.initials: J
authors.lastname: Shi
authors.forename: Bingyin
authors.initials: B
authors.lastname: Shi
authors.forename: Na
authors.initials: N
authors.lastname: Wang
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Guanjun
authors.initials: G
authors.lastname: Zhang
authors.forename: Meiju
authors.initials: M
authors.lastname: Ji
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.forename: Nongyue
authors.initials: N
authors.lastname: He
authors.forename: Peng
authors.initials: P
authors.lastname: Hou
mesh_terms: D000368:Aged; D001483:Base Sequence; D019175:DNA Methylation; D017931:DNA Primers; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics / Q000473:pathology* / Q000628:therapy; D016896:Treatment Outcome
chemical_list: D017931:DNA Primers