MMP9 and Alzheimer disease: In the present study, the effect of AD on PMA-induced H3255 cell proliferation was investigated, and it was demonstrated that (i) AD is able to inhibit the expression and activity of MMP-9 and (ii) AD is capable of inhibiting NF-κB-mediated MMP-9 expression by suppressing the activation of NF-κB, and thus preventing the migration and invasion of tumor cells.