Compared with those in the ulinastatin group, the viability of breast cancer cells was lowered, the positive rate of EdU staining was reduced, the positive rate of Hoechst 33258 staining was raised, and the mRNA and protein levels of ERK and FOXO3 in breast cancer cells clearly declined in the ulinastatin+ERK inhibitor group. Here, FOXO3 is linked to breast cancer.