[Role of cyclooxygenase-2 (COX-2) and peroxisome proliferator-activated receptor (PPAR) in gastric cancer].
OBJECTIVE
Gastric cancer is still the most frequently diagnosed malignancy in Korea. It has been reported that COX-2 and PPAR are involved in multi-step gastric carcinogenesis. The aim of the present study was to examine the expression of COX-2 and PPAR in gastric cancer.


METHODS
A total of 75 subjects including 45 patients with gastric cancer and 30 controls were enrolled. All subjects underwent upper gastrointestinal endoscopic examination with tissue collection. mRNA extraction from the tissues and real-time PCR for COX-2, PPAR-delta, and PPAR-gamma were performed. Gastric mucosal concentration of PGE2, which is a final product of COX-2, and 15d-PGJ2, which is a ligand of PPAR-gamma, were measured by the enzyme immunoassay method.


RESULTS
COX-2 mRNA expression was significantly higher in both early gastric cancer tissues (EGC, 8.32 +/- 4.84 micro gram/micro L, p<0.005) and advanced gastric cancer tissues (AGC, 8.16 +/- 2.67 micro gram/micro L, p<0.001) than in non-cancerous tissues of controls (3.46 +/- 1.72 micro gram/micro L). There was no significant difference of PPAR-delta and PPAR-gamma mRNA expression between gastric cancer tissues and controls. Mucosal PGE2 concentration was significantly higher in both EGC tissues (5.31 +/- 0.49 micro gram/mg protein, p<0.001) and AGC tissues (5.46 +/- 0.54 micro gram/mg protein, p<0.001) than in non-cancerous tissues of controls (4.22 +/- 0.8 micro gram/mg protein). There was no significant difference of 15d-PGJ2 concentration between gastric cancer tissues and controls.


CONCLUSIONS
COX-2 overexpression and increased PGE2 concentration in gastric tissues may play an important role in gastric carcinogenesis. However, the role of PPAR (delta and gamma) and 15d-PGJ2 in gastric carcinogenesis is uncertain. Further studies are needed.
Chang
Young Woon
YW
Department of Internal Medicine, Kyung Hee University College of Medicine, Seoul, Korea. cywgi@chollian.net
Cho
Hwoang Lae
HL
Jang
Jae Young
JY
Dong
Seok Ho
SH
Kim
Hyo Jong
HJ
Kim
Byung Ho
BH
Lee
Joung Il
JI
Chang
Rin
R
D000328:Adult; D000368:Aged; D051546:Cyclooxygenase 2; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism*; D006801:Humans; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D047492:Peroxisome Proliferator-Activated Receptors / Q000378:metabolism*; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D013274:Stomach Neoplasms / Q000378:metabolism*
D008565:Membrane Proteins; D047492:Peroxisome Proliferator-Activated Receptors; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases