title: Age-related methylation patterning of housekeeping genes and tissue-specific genes is distinct between the stomach antrum and body.
abstract: OBJECTIVE
  The methylation-variable sites around CpG islands are frequently overmethylated in Helicobacter pylori-infected stomachs. Age-related patterns of the overmethylation changes were compared between the fast-growing antrum cells and the slow-growing body cells.
  
  
  METHODS
  A total of 316 H. pylori-positive tissues and 380 H. pylori-negative tissues were obtained by endoscopic biopsy. The methylation-variable sites of ten housekeeping genes and nine tissue-specific genes were semiquantitatively analyzed, based on the ten-level classification of methylation-specific PCR intensity. The overmethylated genes were scored when their methylation levels were higher than an intermediate level of each gene common in the H. pylori-negative mucosa.
  
  
  RESULTS
  The age-dependent methylation level of the inactive APC gene observed similarly in the antrum and the body was used as an age standard of methylation variation in a biopsy tissue. The overmethylation of housekeeping genes and stomach-specific genes rapidly increased to a high plateau frequency in the young-aged APC methylation cases (mean age: 43 years) in the H. pylori-positive antrum. In the H. pylori-positive body, most of the overmethylated housekeeping genes slowly increased to a peak frequency in the middle-aged APC methylation cases (mean age: 53 years). The housekeeping gene pairs showed high correlations (Spearman's correlation coefficient > 0.4) in both the antrum and the body.
  
  
  CONCLUSIONS
  The overmethylation of housekeeping genes rapidly and slowly increased to a high frequency in concordance with a rapid and slow growth of epithelial cells in the H. pylori-infected stomach.
authors.affiliation: Department of Microbiology, College of Medicine, The Catholic University of Korea, 505 Banpo-dong Socho-gu, Seoul 137-701, Republic of Korea.
authors.forename: Seung-Jin
authors.initials: SJ
authors.lastname: Hong
authors.forename: Hwa-Jeong
authors.initials: HJ
authors.lastname: Lee
authors.forename: Jung-Hwan
authors.initials: JH
authors.lastname: Oh
authors.forename: Sung-Hoon
authors.initials: SH
authors.lastname: Jung
authors.forename: Ki-Ouk
authors.initials: KO
authors.lastname: Min
authors.forename: Sang-Wook
authors.initials: SW
authors.lastname: Choi
authors.forename: Mun-Gan
authors.initials: MG
authors.lastname: Rhyu
mesh_terms: D000328:Adult; D000375:Aging; D018899:CpG Islands; D019175:DNA Methylation; D005753:Gastric Mucosa / Q000378:metabolism*; D020043:Genes, Essential / Q000235:genetics*; D016481:Helicobacter Infections / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D016480:Helicobacter pylori; D006801:Humans; D008875:Middle Aged; D011706:Pyloric Antrum / Q000378:metabolism*; D018626:Retroelements / Q000235:genetics
chemical_list: D018626:Retroelements