Expression of cyclooxygenase-2 and clinicopathologic features in human gastric adenocarcinoma

AIM: To study the expression of cyclooxygenase-2 (COX-2)gene in gastric cancer and the relationship between COX-2expression and clinicopathologic features of gastric cancer.METHODS: With reference to the expression of β-actin gene,COX-2 mRNA level was examined in cancerous tissues andadjacent noncancerous mucosa from 33 patients bysemiquantitative reverse transcription- polymerase chainreaction (RT-PCR). Quantitation of relative band Adj volumecounts was performed using molecular Analyst for windowssoftware. The COX-2 index was determined from the band Adjvolume counts ratio of COX-2 to constitutively expressed actin.RESULTS: The COX-2 index in gastric carcinoma wassignificantly higher than that in normal mucosa (0.5966±0.2659vs 0.2979+0.171, u=5.4309, P＜0.01). Significantly higherexpression of COX-2 mRNA was also observed in patientswith lymph node involvement than that in those without(0.6775±0.2486 vs 0.4105±0.2182, t=2.9341, P＜0.01).Furthermore, the staging in the UICC TNM classificationsignificantly correlated with COX-2 overexpression (F＝3.656,P＜0.05), the COX-2 index in stage Ⅲ and IV was significantlyhigher than those in stage Ⅰ and Ⅱ(q=3.2728 and q=3.4906, P＜0.05). The COX-2 index showed no correlationwith patient's age, sex, blood group, tumor location, grosstyping, depth of invasion, differentiation, and the greatesttumor dimension (P＞0.05).CONCLUSION: Expression of COX-2 mRNA in gastriccarcinoma was significantly higher, which may enhancelymphatic metastasis in patients with gastric carcinoma. Thestaging in the UICC TNM classification was significantlycorrelated with COX-2 over-expression. COX-2 may contributeto progression of tumor in human gastric adenocarcinoma.