title: EBV-infection in cardiac and non-cardiac gastric adenocarcinomas is associated with promoter methylation of p16, p14 and APC, but not hMLH1.
abstract: BACKGROUND
  Epstein-Barr virus (EBV)-associated gastric carcinomas (GC) constitute a distinct clinicopathological entity of gastric cancer. In order to determine underlying distinct aberrant promoter methylation we tested cardiac and non-cardiac GC with regard to the presence of EBV.
  
  
  METHODS
  One hundred GC were tested by RNA- in situ hybridization for the presence of EBV by EBV-encoded small RNA (EBER). Aberrant promoter methylation was investigated by methylation-specific real-time PCR for p16, p14, APC and hMLH1. P16 protein expression was assessed by immunohistochemistry.
  
  
  RESULTS
  In our selected study cohort, EBER-transcripts were detected in 19.6% (18/92) of GC. EBV-positive GC revealed significantly more often gene hypermethylation of p16, p14 and APC (p < 0.0001, p < 0.0001, and p = 0.02, respectively) than EBV-negative GC. The majority of GC with p16 hypermethylation showed a p16 protein loss (22/28). In contrast, no correlation between the presence of EBV and hMLH1 hypermethylation was found (p = 0.7). EBV-positive GC showed a trend towards non-cardiac location (p = 0.06) and lower stages (I/II) according to the WHO (p = 0.05).
  
  
  CONCLUSIONS
  Hypermethylation of tumor suppressor genes is significantly more frequent in EBV-associated GC compared to EBV-negative GC. Our data add new insights to the role of EBV in gastric carcinogenesis and underline that EBV associated GC comprise a distinct molecular-pathologic as well as a distinct clinicopathological entity of GC.
authors.affiliation: Institute of Pathology, University Hospital of Düsseldorf, Germany. Helene.Geddert@vincentius-ka.de
authors.forename: Helene
authors.initials: H
authors.lastname: Geddert
authors.forename: Axel
authors.initials: A
authors.lastname: zur Hausen
authors.forename: Helmut E
authors.initials: HE
authors.lastname: Gabbert
authors.forename: Mario
authors.initials: M
authors.lastname: Sarbia
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics; D025601:Adenomatous Polyposis Coli Protein / Q000235:genetics; D000328:Adult; D000368:Aged; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics; D019175:DNA Methylation / Q000235:genetics*; D020031:Epstein-Barr Virus Infections / Q000150:complications* / Q000235:genetics; D005260:Female; D006801:Humans; D017403:In Situ Hybridization; D008297:Male; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D009363:Neoplasm Proteins / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics; D011401:Promoter Regions, Genetic; D013274:Stomach Neoplasms / Q000150:complications / Q000235:genetics* / Q000473:pathology / Q000821:virology*; D025803:Tumor Suppressor Protein p14ARF / Q000235:genetics
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D025601:Adenomatous Polyposis Coli Protein; D019941:Cyclin-Dependent Kinase Inhibitor p16; C501486:MLH1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D025803:Tumor Suppressor Protein p14ARF; D000070957:MutL Protein Homolog 1