Abstract: Objective To investigate the effect of 5 fluorouracil on the biological characteristics of BEL-7402 and SMMC-7721 cell line. Methods The proliferation of the two cell lines with 5-FU treatment was detected by cell counting Kit-8;the cell cycle and the ratio of cells with positive expression of tumor stem cell surface markers,EpCAM,ABCG2 and ICAM-1 were detected by flow cytometry. Results The proliferation of the two cell lines at 10μg.ml^-1 5-FU treatment was obviously inhibited;the ratio of the rest phase cells（G0/G1 phase）in the experimental group was significantly higher than in the control group（P<0.05）. Meanwhile,the proportion of EpCAM,ABCG2 and ICAM-1 positive cells increased as compared to control group（P<0.05）. Conclusion Tumor stem cell population in BEL-7402 and SMMC-7721 cell line can escape from the killing effect of 5-FU,which might be a vital important cause of chemotherapy failure in clinic practice.

Key words: BEL-7402 cell line, SMMC-7721 cell line, Tumor stem cell, 5-fluorouracil