MMP9 and prostate cancer: And then utilizing in vitro and in vivo experimental systems, we show that ALDH1A1 promoted invasion and metastasis of prostate cancer by activating the RARα, which further activated Ets1, MMP9 and Silybin inhibited the expression of ALDH1A1 in prostate cancer, thereby inhibiting the activation of RAR and preventing the activation of Ets1 to inhibit the growth and invasion of prostate cancer.