To study the possible role of MMPs in RUNX3-induced inhibition of cell metastasis, ECM degradation is an essential step in tumor invasion and metastasis, which was mainly mediated by the balance between some matrix metalloproteinases (MMPs), such as MMP2 and MMP9 [13], [14] and tissue inhibitors of matrix metalloproteinases (TIMPs), such as TIMP1 and TIMP2 [17], [18]. Here, MMP9 is linked to neoplasm.