MMP9 and breast cancer: Thus, oxidant-mediated apoptosis limits tumor transformation and metastasis, as confirmed by histological analysis of the marked elimination of mammary tumor cells with complete inhibition of their metastasis to liver or lung, and immunostaining Ki-67 decline with the lowest MMP9 expression and hepatic tumor marker (AFP) level in MT-CD NPs group, compared to MT-ZD NPs and MT-Fu.