Objective:To investigate the expression of maspin,uPA and MMP-7 in gastric carcinoma and discuss their roles in tumorigenesis and progression of gastric cancer. Methods:Immunohistochemistry SP method was used to detect expression of maspin,uPA and MMP-7 in gastric adenocarcinoma(n=30),signet-ring cell carcinoma(n=30),normal gastric mucosa(n=20);in addition,reverse transcriptase PCR was carried out to compare the mRNA expression of maspin between gastric adenocarcinoma and normal mucosa. Results:The expression rates of maspin.uPA and MMP-7 protein were 50%,70% and 80% in gastric adenocarcinoma,and 46.7%,76.7%,and 90% in signet-ring cell carcinoma, respectively.However,the expression rates of maspin,uPA,and MMP-7 protein were 90%,35%and 30%,respectively in normal gastric mucosa.The relative transcription level of maspin mRNA in normal gastric mucosa was higher than that in gastric adenocarcinoma(P＜0.01).Maspin protein expression was significantly related to the depth of invasion and lymph node metastasis of gastric carcinoma,but did not relate to tumor size and TNM staging. The protein expression of nPA and MMP-7 were significantly related to invasive depth,lymph node metastasis and TNM staging of carcinoma,but not to tumor size. Maspin protein expression had a negative correlation with uPA and MMP-7,while uPA protein expression had a positive correlation with MMP-7.The relative mRNA transcription level of Maspin significantly correlated with the lymph node metastasis and the depth of invasion of carcinoma,but did not relate to TNM staging or tumor size. Conclusion:Down-regulated expression of maspin and up- regulated expression of uPA and MMP-7 play important roles in the invasion and metastasis of gastric carcinoma. They may serve as effective markers of the biopathological behavior of gastric tumor.