MMP9 and neoplasm: In parallel, the effect of MC4040 and MC4041 on epithelial to mesenchymal transition (EMT) was analysed determining, in GL1 and U87 cells, the levels of E-cadherin as epithelial marker, of N-cadherin as mesenchymal marker, and of matrix metalloproteinases (MMPs), specifically MMP2, MMP3, and MMP9, basally upregulated in GL1 and U87 cells, and usually highly expressed in the majority of aggressive tumours and responsible for tumour invasiveness [15].