MMP2 and osteosarcoma: Chen et al. further confirmed that kaempferol attenuated the MAPK signaling pathways including ERK, JNK, and p38, resulting in decreased DNA binding ability of AP-1, and, hence, the downregulation of the expression and enzymatic activities of MMP-2, MMP-9, and Upa, contributing to the inhibition of metastasis of osteosarcoma cells [51].