During EMT, cancer cells lose their cell-to-cell attachment by decreasing E-cadherin expression, due to hypermethylation of the promoter region or transcriptional repression caused by Zinc finger E-box-binding homeobox 1 (ZEB1), ZEB2, Snail, Slug (also known as SNAI2), and TWIST [45,46]. This evidence concerns the gene SNAI1 and cancer.