AIM: To study the effect of the transfected Twist gene on invasion and metastasis of gastric carcinoma cells and the possible mechanisms involved.METHODS: Human gastric carcinoma MKN28 cells were stably transfected with Twist sense plasmid, and MKN45 cells were stably transfected with Twist antisense plasmid using the lipofectamine transfection technique.RT-PCR,Western blotting, ENSA, gelatin zymography assay, and in vitro invasion and migration assays were performed.Nude mice metastasis models were established by the abdominal cavity transfer method.RESULTS: Cell models (TwistS-MKN28) that steadily expressed high Twist protein were obtained.Compared with MKN28 and pcDNA3-MKN28 cells, adherence,migration and invasion ability of TwistS-MKN28 cells were clearly raised.The number of cancer nodules was increased significantly in the abdominal cavity and liver of nude mice inoculated with TwistS-MKN28 cells.Overexpression of Twist in MKN28 cells increased Tcf-4/Lef DNA binding activity, and promoted expression of Tcf-4's downstream target genes cyclin Dt and HMP-2.However, suppression of Twist (TwistAS-NKN45) inhibited MKN45 cell invasion and the expression of cyclin D1 was reduced.The activity of MMP-2 was also decreased.CONCLUSION: These results indicate that Twist promotes gastric cancer cell migration, invasion and metastasis, and Twist may play an important role in Wnt/Tcf-4 signaling.