Yang et al. (2018) also indicated that the migration, invasion ability of PCa cells could be inhibited by downregulated the expression of MMP9. As expected, Silybin presented inhibition of ALDH1A1 expression and along with the lower expressions of RARα, Ets1 and MMP9. Therefore, these results consistently demonstrated Silybin had therapeutic effect on prostate cancer by downregulated the expression of ALDH1A1 in vivo and vitro. This evidence concerns the gene MMP9 and prostate cancer.