SNAI1 and cancer: However, two studies in 2015, one using lineage tracing with Fsp1 or Vimentin promoter driving Cre recombinase (Fsp1-Cre or Vim-Cre) and the other using genetically engineered mouse models with deletion of Snail or Twist gene, demonstrated that EMT is not required for cancer metastasis but contributes to chemoresistance [67, 140].