Thus, the next step involves defining the putative experimental threshold of selected EMT hallmarks (EMT-TFs SNAI1, SNAI2, TWIST1, and ZEB1), mesenchymal markers (VIM, hFN1, CDH2, CDH5, and MCAM), and the metallo-proteinases (MMP2 and MMP9) that can be applied for cancer patients′ stratification based on cancer aggressiveness or response to therapies. This evidence concerns the gene SNAI1 and cancer.