title: Histopathology and expression of Ki-67 and cyclooxygenase-2 in childhood Helicobacter pylori gastritis.
abstract: BACKGROUND
  Helicobacter pylori infection has been implicated in many pathobiologic changes that are linked with the pathogenesis of gastric cancer. The majority of studies have been performed in adults; however, H. pylori infection in children may be of greater significance because, in general, it reflects the early phase of infection. We therefore investigated several pathobiologic changes in the gastric mucosa of H. pylori-infected children, including histopathologic features, cell proliferation-associated Ki-67 antigen expression, and cyclooxygenase (COX)-2 expression.
  
  
  METHODS
  Sixty-five children with nonulcer dyspepsia were included; 52 were infected with H. pylori, while the other 13 were free of H. pylori infection. A histopathologic review of biopsy specimens obtained from the gastric antrum was performed according to the updated Sydney system. Immunohistochemical expressions of Ki-67 and COX-2 were scored quantitatively or semiquantitatively.
  
  
  RESULTS
  The H. pylori-infected group was significantly associated with a higher grade of chronic inflammation, acute inflammation, and glandular atrophy. Ki-67 and COX-2 expressions were found to be significantly higher in the H. pylori-infected group. COX-2 expression was correlated with acute and chronic inflammation and Ki-67 expression. COX-2 expression was observed mainly in the monocytic cells and myofibroblasts in the lamina propria.
  
  
  CONCLUSIONS
  H. pylori-infected children, suggestive of the early phase of infection, exhibit increased gastric epithelial cell proliferation, increased COX-2 expression, and other pathobiologic features that may contribute to gastric carcinogenesis. These results have clinical significance for the early introduction of eradication of H. pylori infection in childhood.
authors.affiliation: Department of Pediatrics, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Kyung Mo
authors.initials: KM
authors.lastname: Kim
authors.forename: Young Lyun
authors.initials: YL
authors.lastname: Oh
authors.forename: Jae Sung
authors.initials: JS
authors.lastname: Ko
authors.forename: Yon Ho
authors.initials: YH
authors.lastname: Choe
authors.forename: Jeong Kee
authors.initials: JK
authors.lastname: Seo
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D051546:Cyclooxygenase 2; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism / Q000473:pathology; D005756:Gastritis / Q000201:enzymology / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology*; D016481:Helicobacter Infections / Q000378:metabolism / Q000473:pathology; D016480:Helicobacter pylori; D006801:Humans; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000378:metabolism*; D019394:Ki-67 Antigen / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*
chemical_list: D007527:Isoenzymes; D019394:Ki-67 Antigen; D008565:Membrane Proteins; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases