EMT process and signaling pathway. During EMT, tubular epithelial cells turn off the expression of adhesion molecules (E-cadherin, claudins and cytokeratins), and upregulate mesenchymal markers such as vimentin (VIM), fibronectin (FN), α-SMA, and fibroblast-specific protein-1 (FSP1). Subsequently, they undergo a reorganization of the cytoskeleton and a change in their morphology. The transition process from epithelial to mesenchymal phenotype is gradual and it involves intermediate morphological changes . Degradation of the tubular basement membrane and migration of the transformed epithelial cells into the interstitium complete the EMT. The table at the bottom summarizes the main EMT triggers and the signaling pathways that they activate.