@@ Chronic infection and inflammation have been regarded as one of main course of carcinogenesis and development.Toll-like receptors(TLR)expressed on inflammatory cells play a key role in host defense against pathogens，benefiting the host.Also，recent studies showed that TLRs were also expressed by tumor cells.However, the mechanisms by which TLR-triggered tumor progression remain to be fully understood.To evaluate the role of TLR in tumor cells.we investigated TLR4 signaling effects on human gastric cancer(GC).TLR4 expression in gastric cancer tissue (n=36)and cell lines(BGC，AGS，SGC，MGC，and MKN45)was detected by immunohistochemistry， RT-PCR,western blots，and FCM.Cell viability was analyzed with cell proliferation CCK8 kit according to the manufacture’S instruction.NF-kB localization data derived from immunohistological analysis graphed aus nucleus：cytoplasm (N∶C) ratio. The NF-kB luciferase reporter gene assay was used to detect the role of LPS on the activity of NF-kB.Supernatants of tumor cells were collected after 48 h of co-incubation with TLR ligands.LPS.