MMP9 and breast cancer: In addition, the serum of the patient not only inhibited the proliferation and invasion of the highly metastatic human MDA-MB-231 breast cancer cells in vitro, causing cell cycle arrest in G0/G1 phase, but also decreased the activation of MMP9/MMP2, Bcl-2/Bax, c-Met receptor, NF-κB expression, and Akt phosphorylation level.