Curcumin inhibits the metastasis of K1 papillary thyroid cancer cells via down-regulating the expression of MMP-9 and up-regulating the expression of E-cadherin, which consequently suppresses the epithelial-mesenchymal transition (EMT) and reduces the viability and migration of tumor cells [122]. The gene discussed is MMP9; the disease is thyroid gland papillary carcinoma.