title: Association of COX2 gene hypomethylation with intestinal type gastric cancer in samples of patients from northern Brazil.
abstract: To verify the methylation status of THBS1, GPX3, and COX2 genes and to evaluate their association with Helicobacter pylori in gastric adenocarcinomas. Methylation-sensitive restriction enzyme PCR assay was performed in 16 diffuse type gastric cancer samples, 23 intestinal type, and 15 normal stomach tissue. The presence of H. pylori was performed by amplification of the fragment of the 16S rRNA. Statistical analyses were performed using Fisher's exact test. The hypermethylation of GPX3, THBS1, and COX2 occurred in 18 (n = 7), 5 (n = 2), and 36 % (n = 14) of gastric cancer samples, respectively, whereas in normal samples, it was found in 13, 7, and 67 %. The presence of H. pylori was detected in 67 % of gastric cancer samples and 67 % in normal gastric samples. The methylation of THBS1 and GPX3 was not significantly different between the types of tumors, normal sample, the presence of H. pylori, or clinicopathological variables studied (P > 0.05). However, the methylation status of the gene COX2 is significantly different between normal tissue and intestinal type gastric cancer (P = 0.02). Therefore, our results suggest that the methylation status of the gene COX2 is associated with the intestinal type of gastric cancer.
authors.affiliation: Graduate Program in Cellular and Molecular Biology and Laboratory of Structural Molecular Biology and Oncogenetics-LBMEO, Department of Molecular Biology, Federal University of Paraíba UFPB, 58051-900, João Pessoa, PB, Brazil.
authors.forename: Cynthia Farias Vieira
authors.initials: CF
authors.lastname: de Melo
authors.forename: Carolina Oliveira
authors.initials: CO
authors.lastname: Gigek
authors.forename: Juarez Nóbrega
authors.initials: JN
authors.lastname: da Silva
authors.forename: Marilia de Arruda
authors.initials: Mde A
authors.lastname: Cardoso Smith
authors.forename: Rubistenia Miranda
authors.initials: RM
authors.lastname: de Araújo
authors.forename: Rommel Rodríguez
authors.initials: RR
authors.lastname: Burbano
authors.forename: Eleonidas Moura
authors.initials: EM
authors.lastname: Lima
mesh_terms: D001938:Brazil; D018899:CpG Islands / Q000235:genetics; D051546:Cyclooxygenase 2 / Q000235:genetics*; D019175:DNA Methylation / Q000235:genetics; D005260:Female; D056726:Genetic Association Studies; D005979:Glutathione Peroxidase / Q000235:genetics*; D016480:Helicobacter pylori / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity; D006801:Humans; D007414:Intestinal Neoplasms / Q000235:genetics* / Q000382:microbiology / Q000473:pathology; D008297:Male; D011401:Promoter Regions, Genetic; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013274:Stomach Neoplasms / Q000235:genetics* / Q000382:microbiology / Q000473:pathology
chemical_list: D012336:RNA, Ribosomal, 16S; C486484:GPX3 protein, human; D005979:Glutathione Peroxidase; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human