MMP9 and neoplasm: Moreover, DA can also suppress neovascularization in tumors by inhibiting mobilization of endothelial progenitor cells (EPCs) from the bone marrow to tumor vascular bed via DA D2 receptor-mediated inhibition of matrix metalloproteinase 9 (MMP-9) synthesis and ERK-1/ERK-2 signaling pathways in these cells [6].