AIM:To observe the anti-cancer effects of COX-2 inhibitorsand investigate the relationship between COX-2 inhibitorsand angiogenesis,infiltration or metastasis in SGC7901cancer xenografts.METHODS:Thirty athymic mice xenograft models withhuman stomach cancer cell SGC7901 were established anddivided randomly into 3 groups of 10 each.Sulindac,onenon-specific COX inhibitor belonging to non-steroidal anti-inflammatory drugs (a series of COX inhibitors known asNSAIDs) and celecoxib,one selective COX-2 inhibitor (knownas SCIs) were orally administered to mice of treatmentgroups.Immunohistochemistry was used to examine theexpression of PCNA,CD44v6 and microvessel density (MVD).Apoptosis was detected by using TUNEL assay.RESULTS:Tumors in sulindac and celecoxib groups weresignificantly smaller than those in control group from thesecond week after drug administration (P<0.01).Intreatment group,the cell proliferation index was lower(P<0.05) and apoptosis index was higher (P<0.05) thanthose in control groups.Compared with the controls,microvessel density was reduced (P<0.01) and expressionof CD44v6 on tumor cells was weakened (P<0.05) intreatment groups.CONCLUSION:COX-2 inhibitors have anticancer effectson gastric cancer.They play important roles in angiogenesisand infiltration or metastasis of stomach carcinoma.Theanticancer effects of COX-2 inhibitors may include inducingapoptosis,suppressing proliferation,reducing angiogenesisand weakening invasiveness. AIM: To observe the anti-cancer effects of COX-2 inhibitors and investigate the relationship between COX-2 inhibitors and angiogenesis, infiltration or metastasis in SGC7901 cancer xenografts. METHODS: Thirty athymic mice xenograft models with human stomach cancer cells SGC7901 were established and divided into 3 groups of 10 each. Sulindac, onenon-specific COX inhibitors belonging to non-steroidal anti-inflammatory drugs (a series of COX inhibitors known as NSAIDs) and celecoxib, one selective COX-2 inhibitor (known as SCIs) were orally administered to mice of treatment groups. Immunohistochemistry was used to examine the expression of PCNA, CD44v6 and microvessel density (MVD) .Apoptosis was detected by using TUNEL assay .RESULTS: Tumors in sulindac and celecoxib groups weresignificantly smaller than those in control group from thesecond week after drug administration (P <0.01 ) .Intreatment group, the cell proliferation index was lower (P <0.05) and apoptosis index was higher (P <0.05) thanthose in cont rol groups. Complicated with the controls, microvessel density was reduced (P <0.01) and expression of CD44v6 on tumor cells was weakened (P <0.05). intreatment groups.CONCLUSION: COX-2 inhibitors have anticancer effects on gastric cancer. The play important roles in angiogenesis and infiltration or metastasis of stomach carcinoma. of the effects of COX-2 inhibitors may include inducing apoptosis, suppressing proliferation, reducing angiogenesis and weakening invasiveness.