Epithelial–mesenchymal transition (EMT) was involved in the invasion and migration of tumor cells; in analyzing the expression of EMT proteins that are critical for initiating metastasis, we found that adiponectin treatment elevated the expression of E-cadherin and Claudin-1 while decreasing the level of N-cadherin, vimentin, MMP-2, MMP-9, Snail, and Slug in S18 and 5-8F cells (Figure 2D), further supporting that adiponectin can impair NPC cell migration and invasion by inhibiting EMT. Here, MMP9 is linked to nasopharyngeal carcinoma.