title: DNA mismatch repair gene methylation in gastric cancer in individuals from northern Brazil.
abstract: Gastric cancer is one of the most common malignancies. DNA methylation is implicated in DNA mismatch repair genes deficiency. In the present study, we evaluated the methylation status of MLH1, MSH2, MSH6 and PMS2 in 20 diffuse- and 26 intestinal-type gastric cancer samples and 20 normal gastric mucosal of gastric cancer patients from Northern Brazil. We found that none of the nonneoplastic samples showed methylation of any gene promoter and 50% of gastric cancer samples showed at least one methylated gene promoter. Methylation frequencies of MLH1, MSH2, MSH6 and PMS2 promoter were 21.74%, 17.39%, 0% and 28.26% respectively in gastric cancer samples. MLH1 and PMS2 methylation were associated with neoplastic samples compared to nonneoplastic ones. PMS2 methylation was associated with diffuse- and intestinal-type cancer compared with normal controls. Intestinal-type cancer showed significant association with MLH1 methylation. Diffuse-type cancer was significantly associated with MSH2 methylation. Our findings show differential gene methylation in tumoral tissue, which allows us to conclude that methylation is associated with gastric carcinogenesis. Methylation of mismatch repair genes was associated with gastric carcinogenesis and may be a helpful tool for diagnosis, prognosis and therapies. However, MSH6 does not seem to be regulated by methylation in our samples.
authors.affiliation: Colegiado de Biomedicina, Universidade Federal do Piauí, Parnaíba, PI, Brasil.
authors.forename: Eleonidas
authors.initials: E
authors.lastname: Moura Lima
authors.forename: Mariana
authors.initials: M
authors.lastname: Ferreira Leal
authors.forename: Marília de Arruda
authors.initials: Mde A
authors.lastname: Cardoso Smith
authors.forename: Rommel
authors.initials: R
authors.lastname: Rodríguez Burbano
authors.forename: Paulo
authors.initials: P
authors.lastname: Pimentel de Assumpção
authors.forename: Maria Jose
authors.initials: MJ
authors.lastname: Bello
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Rey
authors.forename: Francinaldo
authors.initials: F
authors.lastname: Ferreira de Lima
authors.forename: Cacilda
authors.initials: C
authors.lastname: Casartelli
mesh_terms: D000328:Adult; D000368:Aged; D001938:Brazil; D019175:DNA Methylation; D053843:DNA Mismatch Repair; D045643:DNA Repair Enzymes / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011401:Promoter Regions, Genetic; D017422:Sequence Analysis, DNA; D013274:Stomach Neoplasms / Q000235:genetics*
chemical_list: D045643:DNA Repair Enzymes