 During this process, epithelial cells lose expression of proteins like E-cadherin, Zonula occludens 1 (ZO1), and cytokeratin.At the same time they turn on the expression of vimentin, alpha smooth muscle actin (ACTA2), and fibroblast-specific protein 1 (FSP1).They also produce extracellular matrix components, such as type I collagen and fibronectin.