title: Helicobacter pylori and EBV in gastric carcinomas: methylation status and microsatellite instability.
abstract: OBJECTIVE
  To verify the methylation status of CDH1, DAPK, COX2, hMLH1 and CDKN2A genes and to evaluate their association with Helicobacter pylori (H. pylori)-cagA(+) and Epstein Barr virus (EBV) infections in gastric adenocarcinomas.
  
  
  METHODS
  Methylation-specific PCR (MSP) assay was performed in 89 primary gastric carcinomas (intestinal and diffuse types). Microsatellite instability (MSI) analysis was performed using the BAT26 primer set and PCR products were analyzed with the ABI PRISM 3100 Genetic Analyzer using Genescan 3.7 software (Applied Biosystems). Detection of H. pylori and genotyping were performed by PCR, using specific primers for ureaseC and cagA genes. The presence of EBV was assessed by in situ hybridization. Statistical analyses were performed using the chi(2) or Fisher's exact test.
  
  
  RESULTS
  The most frequent hypermethylated gene was COX-2 (63.5%) followed by DAPK (55.7%), CDH1 (51%), CDKN2A (36%) and hMLH1 (30.3%). Intestinal and diffuse adenocarcinomas showed different methylation profiles and there was an association between methylation of E-CDH1 and H. pylori-cagA(+) in the intestinal adenocarcinoma type. MSI was correlated with hMLH1 methylation. There was an inverse correlation between DAPK hypermethylation and MSI.
  
  
  CONCLUSIONS
  We found a strong association between CDH1 methylation and H. pylori-cagA(+) in intestinal-type gastric cancer, association of MSI and better prognosis and an heterogeneous COX-2 overexpression.
authors.affiliation: Blood Transfusion Center, Botucatu Medical School, UNESP - Sao Paulo State University, Distrito de Rubião Júnior, s/n, 18618-970 Botucatu-SP, Brazil.
authors.forename: Adriana Camargo
authors.initials: AC
authors.lastname: Ferrasi
authors.forename: Nídia Alice
authors.initials: NA
authors.lastname: Pinheiro
authors.forename: Silvia Helena Barem
authors.initials: SH
authors.lastname: Rabenhorst
authors.forename: Otávia Luisa
authors.initials: OL
authors.lastname: Caballero
authors.forename: Maria Aparecida Marchesan
authors.initials: MA
authors.lastname: Rodrigues
authors.forename: Fabrício
authors.initials: F
authors.lastname: de Carvalho
authors.forename: Celso Vieira de Souza
authors.initials: CV
authors.lastname: Leite
authors.forename: Marcia Valéria Pitombeira
authors.initials: MV
authors.lastname: Ferreira
authors.forename: Marcos Aurélio Pessoa
authors.initials: MA
authors.lastname: Barros
authors.forename: Maria Inês Moura Campos
authors.initials: MI
authors.lastname: Pardini
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D000230:Adenocarcinoma / Q000235:genetics* / Q000382:microbiology / Q000821:virology; D015703:Antigens, CD; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000235:genetics / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000378:metabolism*; D064550:Death-Associated Protein Kinases; D020031:Epstein-Barr Virus Infections / Q000150:complications; D005260:Female; D016481:Helicobacter Infections / Q000150:complications; D016480:Helicobacter pylori / Q000302:isolation & purification*; D004854:Herpesvirus 4, Human / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000235:genetics* / Q000382:microbiology / Q000821:virology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D015703:Antigens, CD; D051017:Apoptosis Regulatory Proteins; C513384:CDH1 protein, human; D015820:Cadherins; D019941:Cyclin-Dependent Kinase Inhibitor p16; D004273:DNA, Neoplasm; C501486:MLH1 protein, human; D009687:Nuclear Proteins; D051546:Cyclooxygenase 2; D064550:Death-Associated Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D000070957:MutL Protein Homolog 1