MMP9 and breast cancer: For example, AT-MSC-exos transferred miR-145 to BC cells and can increase miR-145 levels in BC cells, which can induce apoptosis and inhibit metastasis of BC by modulating the Rho-Associated Coiled-Coil Containing Protein Kinase 1 (ROCK1), Erb-B2 Receptor Tyrosine Kinase 2 (ERBB2), Matrix Metalloproteinase 9 (MMP9), and Tumor Protein p53 (TP53) expression [121].