In the tumor microenvironment, exogenous DCN can activate the expression of angiogenesis inhibitors such as thrombospondin-1 (TSP-1) and tissue metalloproteinase tissue inhibitors of matrix metalloproteinase-3 (TIMP-3), while inhibiting pro-angiogenic substances like matrix metalloproteinase-9 (MMP-9) and matrix metalloproteinase-2 (MMP-2). The gene discussed is MMP9; the disease is neoplasm.