SNAI1 and cancer: An important mediator of EMT and E-cadherin downregulation in cancer is the zinc finger transcription factor snail. An example of snail's important role in EMT and control of E-cadherin has been shown in snail knock-out mice which show embryonic lethality, and the embryos fail to complete EMT, forming an altered mesodermal layer while still retaining E-cadherin expression.