Fig. 2

ZEB1-involved EMT and mesenchymal-epithelial transition (MET) processes. In primary breast cancer, the increased ZEB1 level suppressed the expression of the epithelial marker E-cadherin and induced the EMT process. The transformed tumor cells with high ZEB1 levels lost their epithelial characteristics, developed a mesenchymal/motile phenotype, and subsequently invaded into lymph or blood vessels. When metastatic breast cancer was formed in a distant location, the ZEB1 expression level was decreased to promote the expression of the epithelial marker E-cadherin and inhibit the expression of the mesenchymal marker Vimentin, occurring the mesenchymal-epithelial transition (MET) process to recover the epithelial features and lose the mesenchymal/motile phenotype with a low ZEB1 level