Abstract: Objective To determine whether quantitative relationship exists between the expressions of 2 cancer stem cell markers,ABCG2 and CD133,and differentiation degrees of gastric cancer.Methods (1)The expressions of ABCG2 and CD133 were detected in 78 cases of human gastric adenocarcinomas by immunoflurescence assay;(2)2 markers were also detected in 3 gastric cancer cell lines,undifferentiated gastric cancer cell line HGC-27,poorly differentiated gastric cancer cell line BGC-823,and moderately-poorly differentiated gastric adenocarcinoma cell line SGC-7901,in vitro by flow cytometric analysis.(3)Gastric xenotransplant cancers in nude mice were constructed to compare the malignancy of 3 separated cell lines.Expressions of 2 markers were detected in vivo by immunoflurescent staining.Results (1)Expressions of 2 markers were generally correlated with the differentiations of gastric cancers.In human gastric adenocarcinoma,the expressions of 2 markers were increased with the elevation of the malignancy grades of gastric cancers.In addition,the expressions of CD133 were higher in diffuse type than those in intestinal type of human gastric cancers.(2)Undifferentiated cell line HGC-27 expressed more markers than moderately-poorly differentiated cell line SGC-7901.(3)The similar result had been observed in xenotransplant tumors which arouse from 3 cell lines.Conclusion The expressions of cancer stem cell markers ABCG2 and CD133 differed in various differentiation degrees of gastric cancers,poorly differentiated gastric cancer expressed relatively more.