MMP9 and neoplasm: With the overexpression of mesenchymal markers (71) such as N-cadherin (N-cad), vimentin (VIM), fibronectin (FN) and α-smooth muscle actin (α-SMA), tumor cells could reconstruct the cytoskeleton, degrade the basement membrane, and remodel extracellular matrix (ECM) by inducing matrix metalloproteinases (MMPs), such as MMP-2 and MMP-9 (72), underlying metastasis to distant organs, stemness maintenance and reversion of chemoresistance (73).