title: [Gene methylation patterns in digestive tumors].
abstract: BACKGROUND
  The loss of tumor suppressor gene function damages the defensive mechanisms that protect the indemnity of genetic material. Promoter gene methylation is one of the inactivation mechanisms of suppressor genes.
  
  
  OBJECTIVE
  To study the methylation pattern of a group of genes in biopsy samples of gastrointestinal tumors.
  
  
  METHODS
  Forty eight gastric, 25 gallbladder, 24 colon and 6 pancreas cancer biopsy samples were randomly selected. The methylation pattern of CDH1, FHIT, CDKN2A, APC and MLH1 genes, was studied using a specific polymerase chain reaction test for methylation. Demographic, morphological and follow up variables of patients bearing the tumors were also analyzed.
  
  
  RESULTS
  The general methylation frequency of CDH1, FHIT, CDKN2A, APC and MLH1 genes was 64.1, 56, 39.8, 18.1 and 34% respectively. In gastric cancer samples there was a correlation between APC gene methylation and well differentiated tumors; between CDH1 methylation and Lauren diffuse type and the presence of three or more metastasic lymph nodes; between FHIT, CDKN2A and CDH1 gene methylation and male gender. In less differentiated gallbladder tumors, the frequency of CDH1 methylation was higher. There was a tendency towards a lower survival in colon and gastric cancer when MLH1 (p =0.07) y CDKN2A (p= 0.06) were methylated, respectively.
  
  
  CONCLUSIONS
  An abnormal methylation pattern was associated with morphological features in gastric and gallbladder cancer and with a tendency towards a lower survival in colon and gastric cancer.
authors.affiliation: Laboratorio de Patología Molecular, Departamento de Anatomía Patología, Facultad de Medicina, Universidad de La Frontera, Temuco, Chile. lcroa@ufro.cl
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Roa S
authors.forename: Patricia
authors.initials: P
authors.lastname: García M
authors.forename: Angélica
authors.initials: A
authors.lastname: Melo A
authors.forename: Oscar
authors.initials: O
authors.lastname: Tapia E
authors.forename: Miguel
authors.initials: M
authors.lastname: Villaseca H
authors.forename: Juan Carlos
authors.initials: JC
authors.lastname: Araya O
authors.forename: Pablo
authors.initials: P
authors.lastname: Guzmán G