To investigate the roles of maspin and kai1 expression in tumorigenesis and progression of gastric cancer. Methods Maspin and kai1 expressions were detected in normal gastric mucosa （n = 182）

gastric dysplasia （n = 69）

and gastric cancer （n = 113） by immunohisto-chemistry. Their expressions were compared with clinicopathological parameters of tumors. Relationship between maspin and kai1 expression was also concerned in gastric cancer. Results The positive rates of maspin expression were 79.8% （145/182）

75.4% （52/69）

and 50.4% （57/113） in normal gastric mucosa

gastric dysplasia

and gastric cancer

while those of kai1 expression were 81.9% （149/182）

65.2% （49/69）

and 58.4% （66/113） in corresponding tissues respectively. Gastric cancer less frequently expressed maspin than the normal gastric mucosa and gastric dysplasia （P < 0.05）

while dysplasia and cancer showed less frequent expression of kai1 than normal mucosa （P < 0.05）. Maspin expression showed negative association with invasive depth

metastasis

Lauren’s and histological classifications （P < 0.05）

but not with tumor size

Borrmann’s classification

growth pattern or TNM staging （P > 0.05）. Kai1 expression was negatively correlated with invasive depth

metastasis

growth pattern

Lauren’s and histo-logical classifications （P < 0.05）

but not with tumor size

Borrmann’s classification or TNM staging （P > 0.05）. Maspin and kai1 were collaboratively expressed in gastric cancer （P < 0.05）. Conclusions Down-regulated expressions of maspin and kai1 play an important role in gastric carcinogenesis. Abnormal expression of maspin and kai1 might have inhibitory effects on invasion and metastasis of gastric cancer and act as an effe-ctive and objective marker to indicate the pathobiological behaviors of gastric cancer.