Keloid scar is a fibrogenesis tumor-like disease featured by invasion to the surrounding skin. Epithelium-to-mesenchymal transition (EMT) is a process which leads to the loss of epithelial cell polarity and cell-cell adhesion. Through the process of EMT, epithelial cells acquire migratory and invasive behavior and are thus able to transform into mesenchymal cells. EMT has a high clinical significance towards keloid treatment.