Taken together, our data are consistent with a model (Figure 6D) in which SFN contributes to inhibition of thyroid cancer cell growth and metastasis through repressing the activity of PI3K/Akt cascade and expression of MMP-2 and -9, increasing p21 expression by activation of MAPK/Erk and MAPK/p38 signaling pathways, and promoting mitochondrial-mediated apoptosis via a ROS-dependent mechanism. Here, MMP2 is linked to thyroid cancer.