OBJECTIVE To investigate the expression of TGF-β1, Snail, E-cadherin and N-cadherin in gastric cancer (GC), and to examine its relationship to malignant features of the tumors.METHODS The expression of TGF-β1, Snail, E-cadherin and N-cadherin proteins was detected in GC and adjacent tissues by immunohistochemical staining, and compared with the clinico- pathological data.RESULTS Positive rates of expression for TGF-β1, Snail, E-cadherin and N-cadherin were 63.5%, 83.3%, 37.5% and 44.8% in GC, and 28.8%,41.3%, 100%, 11.3% in adjacent tissues, respectively. The expression of all four proteins showed a significant difference between the GCs and adjacent tissues (P＜0.05). The positive rate of TGF-β1, Snail and N-cadherin, or the negative rate of E-cadherin expression was significantly related to the differentiated degree, histological type, invasion and metastasis of GC. In addition, the expression of N-cadherin was positively related to that of TGF-β1,but negatively related to that of E-cadherin. There was negative correlation between expression of E-cadherin and TGF-β1 and Snail in GC (P＜0.05).CONCLUSION The over-expression of TGF-β1 and Snail and decreased expression of E-cadherin and the abnormal expression of N-cadherin were involved in the process of invasion and metastasis of GC. The data showed that E-cadherin might switch to N-cadherin. TGF-β1 and Snail might play a fundamental role in the process.