Abstract: Objective: To observe the expression and significance of EphA2 and its ligand EphrinA1 in gastric carcinoma and to in-vestigate the relationship between the expression of these two proteins and clinicopathologic features. Methods: We used immunohistochemistry (IHC) to detect the expression of EphA2, EphrinA1 and E-cadherin in gastric carcinoma tissues, adjacent tissues and normal gastric mucosa from 82 cases of gastric cancer.From the 82 cases, we randomly selected 45 cases for detection of the above three proteins by flow cytometry (FCM).SPSS was employed to analyze the data. Results: The expression of EphA2 and EphrinA1 was higher in gastric carcinoma tissues than in adjacent tissues and normal gas-tric tissues (P<0.01, P<0.01).E-cadherin expression was lower in gastric carcinoma tissues than in adjacent tissues and normal gastric tissues (P<0.01, P<0.01).No statistical significance was found in the expression of EphA2, EphrinA1 and E-cadherin between adjacent tissues and normal gastric tissues (P>0.05, P>0.05, P>0.05).With decreasing histological differentiation, the expression of EphA2 and EphrinA1 in carcinoma tissues was increased significantly (P<0.05), while the E-cadherin expression was reduced significantly (P<0.05).With increasing depth of infiltration, the expression of EphA2 and EphrinA1 was enhanced significantly (P<0.05), while E-cadherin expression was reduced significantly (P<0.05).The expression of EphA2 and EphrinA1 was higher in carcinomas with lymph node metastasis than in those without lymph node metastasis.The expression of these three proteins was not correlated with tumor diameter, age or gender (P>0.05).EphA2 expression was negatively correlated with the expression of E-cadherin (r=-0.231, P<0.01).A negative correlation was also found between the expression of EphrinA1 and E-cadherin (r=-0.403, P<0.01).The expression of EphA2 was positively correlated with EphrinA1 expression (r=0.707, P<0.01). Conclusion: The abnormal expression of EphA2, Ephri-nA1 and E-cadherin may be involved in the carcinogenesis and metastasis of gastric cancer.Detection of these three pro-teins can provide valuable information for the evaluation of malignant degree and metastatic potential of gastric carcinoma.