Helicobacter pylori and EBV in gastric carcinomas: methylation status and microsatellite instability.
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.
Ferrasi
Adriana Camargo
AC
Blood Transfusion Center, Botucatu Medical School, UNESP - Sao Paulo State University, Distrito de Rubião Júnior, s/n, 18618-970 Botucatu-SP, Brazil.
Pinheiro
Nídia Alice
NA
Rabenhorst
Silvia Helena Barem
SH
Caballero
Otávia Luisa
OL
Rodrigues
Maria Aparecida Marchesan
MA
de Carvalho
Fabrício
F
Leite
Celso Vieira de Souza
CV
Ferreira
Marcia Valéria Pitombeira
MV
Barros
Marcos Aurélio Pessoa
MA
Pardini
Maria Inês Moura Campos
MI
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
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