An acute and chronic liver injury such as hepatitis virus infection, alcohol or non-alcoholic steatohepatitis activates HSC after repeated stimulation, and then HSC gradually differentiates into myofibroblasts, resulting in abnormal distribution and accumulation of hepatic extracellular matrix (collagen, glycoprotein, proteoglycans, etc) [28]. The gene discussed is ART4; the disease is medical procedure.