STAT3 and breast cancer: Moreover, it has been reported that focal adhesion kinase/MMP-involved pathway is critical for cancer invasion and metastasis.28, 44 MMP-2 and MMP-9 upregulation can particularly enhance tumor cell metastatic potential in breast cancer.45 In addition, constitutive Stat3 also has an important role in controlling cell migration and invasion.30 In this study, nifuroxazide not only decreased expression of Stat3 phosphorylation at tyrsione residue 705 but also downregulated MMP-2 and MMP-9 expression in 4T1 cells.