Association of cyclooxygenase-2 expression with Hp-cagA infection in gastric cancer.
OBJECTIVE
To observe the expression of cyclooxygenase-2 (COX-2) and to investigate the association between COX-2 expression and infection with cytotoxic-associated gene A (cagA) positive strain Helicobacter pylori (Hp) in human gastric cancer, and subsequently to provide fresh ideas for the early prevention of gastric cancer.


METHODS
32 Specimens of gastric cancer and corresponding adjacent normal gastric mucosa were obtained from patients who had undergone surgical operations of gastric cancer. All the samples including 1 case of stomach malignant lymphoma and 31 cases of gastric adenocarcinoma were confirmed by pathology diagnosis. The expression of COX-2 in 32 specimens of gastric cancer and corresponding adjacent normal gastric mucosa was quantitatively determined and analyzed with Flow Cytometry, and the levels of COX-2 protein were compared between specimens with cagA(+) Hp infection and those without cagA(+) Hp infection. The cagA gene in 32 specimens of gastric cancer was detected by polymerase chain reaction (PCR) method.


RESULTS
Twenty-seven of 32 (84 %) specimens of gastric cancer showed over-expression of COX-2, compared with the adjacent normal gastric mucosa. cagA(+) gene were detected from 19 specimens of gastric cancer, but not from the other 13 specimens. The levels of COX-2 protein in 19 specimens of gastric cancer with cagA(+) Hp infection (the number of positive cells was 73.82+/-18.2) were significantly higher than those in the 13 specimens without cagA(+) Hp infection (the number of positive cells was 35.92+/-22.1).


CONCLUSIONS
COX-2 is overexpressed in gastric cancer and cagA(+) Hp infection could up-regulate the expression of COX-2 in gastric cancer in human. There may also exist another way or channel to regulate the expression of COX-2 in gastric cancer in addition to cagA(+) Hp infection. Therefore, applying COX-2 selective inhibitors could be an effective and promising way to prevent gastric cancer.
Guo
Xiao-Lin
XL
Cancer Institute, the First Hospital, China Medical University, Shenyang 110001, Liaoning Province, China.
Wang
Li-Er
LE
Du
Shu-Yan
SY
Fan
Chen-Ling
CL
Li
Li
L
Wang
Peng
P
Yuan
Yuan
Y
D000368:Aged; D000942:Antigens, Bacterial / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics*; D051546:Cyclooxygenase 2; D005260:Female; D016481:Helicobacter Infections / Q000201:enzymology*; D016480:Helicobacter pylori / Q000235:genetics*; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D013274:Stomach Neoplasms / Q000382:microbiology*
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D007527:Isoenzymes; D008565:Membrane Proteins; C080866:cagA protein, Helicobacter pylori; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases