Objective By observing the effectiveness of epidermal growth factor(EGF)combined with 5-flauouracil(5-FU)in the treatment of human colorectal cancer,to explore the anti-tumor effects of EGF.Methods MTT assay was used to evaluate the effects of EGF and 5-FU alone or combined use on the growth of tumor cells.The effects of EGF on PCNA expression were detected by Western blot,and flow cytometry was done to measure the changes in cell cycle.Results EGF could induce proliferation of tumor cells.With the increase in concentration of EGF,the number of cells in G0 phase was significantly reduced,and the expression of PCNA obviously increased.There was significant difference between 100 or 1 000 ng/mL EGF groups and control group(P＜0.05).The combined use of EGF and 5-FU could more significantly inhibited the growth of tumor cells than 5-FU alone(P＜0.05).Conclusion EGF can enhance the sensitivity of colorectal cancer cell Caco-2 to 5-FU,which might be related to the induction of proliferation of quiescent colorectal cancer cells.