Olmeda et al. reported that silencing of Snail decreased vimentin in the human breast carcinoma in an in vitro study.22 Protease enzymes have a critical role in this process, in which extracellular matrix and its components facilitate metastasis of tumor cells to other tissues.28 The precise role of proteases, especially MMPs, has been completely verified in metastasis and cancer cell invasion. This evidence concerns the gene SNAI1 and breast carcinoma.