MMP9 and central nervous system cancer: Mangiferin inhibits MMP-9 expression in prostate cancer cells by suppressing NF-κB activity [28], inhibits MMP-9 expression in glioma cells by promoting microRNA-15b (miR-15b) level [29], and inhibits MMP-9 expression in breast cancer cells by weakening the activation of β-catenin pathway and reversing the process of epithelial-mesenchymal transition (EMT) [30].