title: Role of metallothionein in Helicobacter pylori-positive gastric mucosa with or without early gastric cancer and the effect on its expression after eradication therapy.
abstract: OBJECTIVE
  Metallothionein (MT) has a proven relationship with various kinds of cancer and reduces tissue damage. Helicobacter pylori (H. pylori) infection is associated with the alteration of gastric epithelial cell cycle events, a condition implicated in the initiation and development of gastric cancer. This study investigates the role of MT in H. pylori-induced gastritis with or without early gastric cancer (ECG) and evaluates the effect on MT expression after eradication therapy.
  
  
  METHODS
  Gastric biopsy samples were immunohistochemically examined for MT expression in 36 H. pylori-negative patients without ECG and 98 positive patients with or without ECG. Real time polymerase chain reaction was performed in 14 antral biopsy samples with or without H. pylori. The severity of gastritis was also evaluated according to the updated Sydney System. In 31 successfully eradicated patients, the above assessment was repeated for two consecutive years.
  
  
  RESULTS
  MT expression was higher in H. pylori-negative patients than in positive patients (P < 0.01). Moreover, in the corpus it was higher in H. pylori-positive patients without ECG compared to those with ECG (P < 0.05). The MT labeling index had a negative correlation with the severity of gastritis (P < 0.01). A positive correlation was shown between the MT labeling index and apoptosis: proliferation ratio (r = 0.41, P < 0.01). The MT labeling index in H. pylori-positive patients was gradually recovered after eradication (P < 0.05).
  
  
  CONCLUSIONS
  The decrease of MT expression cannot prevent tissue damage in H. pylori-positive gastric mucosa and leads to more severe gastritis. This phenomenon may be attributed to gastric carcinogenesis. H. pylori eradication increases MT expression and may reduce the risk of ECG.
authors.affiliation: Departments of Clinical Molecular Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Mitani
authors.forename: Daisuke
authors.initials: D
authors.lastname: Shirasaka
authors.forename: Nobuo
authors.initials: N
authors.lastname: Aoyama
authors.forename: Ikuya
authors.initials: I
authors.lastname: Miki
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Morita
authors.forename: Nobunao
authors.initials: N
authors.lastname: Ikehara
authors.forename: Yuko
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Okuno
authors.forename: Masanori
authors.initials: M
authors.lastname: Toyoda
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Miyachi
authors.forename: Shiei
authors.initials: S
authors.lastname: Yoshida
authors.forename: Naoko
authors.initials: N
authors.lastname: Chayahara
authors.forename: Junko
authors.initials: J
authors.lastname: Hori
authors.forename: Takao
authors.initials: T
authors.lastname: Tamura
authors.forename: Takeshi
authors.initials: T
authors.lastname: Azuma
authors.forename: Masato
authors.initials: M
authors.lastname: Kasuga
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D005753:Gastric Mucosa / Q000382:microbiology*; D016481:Helicobacter Infections / Q000150:complications / Q000188:drug therapy* / Q000378:metabolism*; D016480:Helicobacter pylori; D006801:Humans; D008668:Metallothionein / Q000096:biosynthesis / Q000502:physiology*; D013274:Stomach Neoplasms / Q000150:complications* / Q000503:physiopathology / Q000517:prevention & control
chemical_list: D000900:Anti-Bacterial Agents; D008668:Metallothionein