Roles of Helicobacter pylori infection and cyclooxygenase-2 expression in gastric carcinogenesis.
OBJECTIVE
Cyclooxygenase (COX)-2 is over expressed in gastrointestinal neoplasm. Helicobacter pylori (H pylori) infection is causally linked to gastric cancer. However, the expression of COX-2 in various stages of H pylori-associated gastric carcinogenesis pathway has not been elucidated. Therefore, the aim of this study was to clarify the role of H pylori induced COX-2 expression during carcinogenesis in the stomach.


METHODS
Gastric biopsies from 138 subjects (30 cases of chronic superficial gastritis (CSG), 28 cases of gastric glandular atrophy (GA), 45 cases of gastric mucosal intestinal metaplasia (IM), 12 cases of moderate gastric epithelial dysplasia and 23 cases of gastric cancer) were enrolled. H pylori infection was assessed by a rapid urease test and histological examination (modified Giemsa staining). The expression of COX-1 and COX-2 in human gastric mucosa was detected by immunohistochemical staining.


RESULTS
H pylori infection rate was 64.3% in GA and 69.5% in gastric cancer, which was significantly higher than that (36.7%) in CSG (P<0.05). The positive expression rates of COX-2 were 10.0%, 35.7%, 37.8%, 41.7% and 69.5% in CSG, GA, IM, dysplasia and gastric cancer, respectively. From CSG to GA, IM, dysplasia and finally to gastric cancer, expression of COX-2 showed an ascending tendency, whereas COX-1 expression did not change significantly in the gastric mucosa. The level of COX-2 expression in IM and dysplasia was significantly higher in H pylori-positive than in H pylori-negative subjects (P<0.01).


CONCLUSIONS
COX-2 expression induced by H pylori infection is a relatively early event during carcinogenesis in the stomach.
Sun
Wei-Hao
WH
Department of Geriatrics, The First Affiliated Hospital of Nanjing Medical University, 300 Guangzhou Road, Nanjing 210029, China. weihaosun@hotmail.com
Yu
Qian
Q
Shen
Hong
H
Ou
Xi-Long
XL
Cao
Da-Zhong
DZ
Yu
Ting
T
Qian
Cheng
C
Zhu
Feng
F
Sun
Yun-Liang
YL
Fu
Xi-Ling
XL
Su
Han
H
D000328:Adult; D000368:Aged; D001706:Biopsy; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D005260:Female; D005753:Gastric Mucosa / Q000382:microbiology / Q000473:pathology; D016481:Helicobacter Infections / Q000453:epidemiology*; D016480:Helicobacter pylori; D006801:Humans; D007527:Isoenzymes / Q000235:genetics*; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D009367:Neoplasm Staging; D018579:Patient Selection; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics*; D013274:Stomach Neoplasms / Q000201:enzymology / Q000382:microbiology* / Q000473:pathology
D007527:Isoenzymes; D008565:Membrane Proteins; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases