MMPs are often upregulated in tumor cells and promote cancer cell migration and invasion through degradation of the extracellular matrix.36 Increased MMP expression has been associated with tumor progression and metastasis, and their inhibition diminished metastatic incidence in several cancer types.37, 38 In our model, the reduction in metastatic tumor burden may be caused, in part, by decreased MMP2 and MMP9 expression, leading to diminished capacity of the cancer cells to migrate and invade. Here, MMP9 is linked to cancer.