MMP9 and breast cancer: In this study, 3-year follow-up showed that the 3-year disease-free survival rate of high TGF- β 1 and MMP-9 subgroup was lower than that of low TGF- β 1 and MMP-9 subgroup, suggesting that there is a certain relationship between the level of serum TGF- β 1 and MMP-9 and prognosis of subjects with BC, which can be used as one of the indexes to judge the prognosis of subjects with BC.