Objective: The purpose of the research is to observe inhibition of Tonglian decoction (TD) on nude mice modeled with gastric cancer cells MGC803 and on proliferating cell nuclear antigen (PCNA) expression in tumor tissue

to provide experimental basis for clinical application of TD. Method: MGC803 cells were inoculated subcutaneously in right forelimbs of all mice. Mice in model group were treated with saline solution 10 mL·kg-1 orally. Mice in positive control group were treated with xiaoaiping tablet at dosage of 10 mL·kg-1

1.80 g·kg-1 (crude drug) of liquid. Mice in TD groups were subdivided as high (1.50 mg·kg-1)

medium (0.75 g·kg-1) and low (0.37 g·kg-1) dose group of drug liquid

with dosage of 10 mL·kg-1. All mice were administrated for 3 weeks and were observed for another 3 weeks continuously. Tumor volumes were measured for 6 weeks every day from the beginning of MGC803 cells transplanted. All mice were killed for isolation of tumor tissue

inhibition ratio of tumor-weight measured. Finally

PCNA expression was examined with immunohistochemistry. Result: TD inhibits tumor growth with positive correlation with time

the inhibitory peak appeared at 4 weeks after medication;tumor weight in TD high-dose group was (1.55±0.68) g

and the inhibition ratio was (58.40±1.56)%

which was significantly different from that in the model group (P<0.05). Positive rate of PCNA expression aslo decreased significantly

showing statistical difference from the model group (P<0.05). Conclusion: TD inhibits tumor growth on nude mice modeled with MGC803

through down regulation of PCNA protein expression.