Golgi membrane protein 1, also known as Golgi membrane protein 73 (GP73), Golgi phosphorylation protein 2, or GOLM1, is a member of the GOLM1/CASC4 family. GP73 is widely expressed in the body, mainly expressed by epithelial cells. GP73 is highly expressed in the colon, prostate, trachea, and stomach, but low in the testes, muscles, lymphatic tissue, white blood cells, and spleen. GP73 is rarely expressed in the liver of normal individuals, but when liver cells are infected with viruses (HBV, HCV), it can cause a sharp increase in GP73 expression. Non viral liver diseases (such as alcoholic liver disease and autoimmune hepatitis) do not cause an increase in the expression of GP73. Therefore, the increased expression of GP73 in liver cells can serve as a sign of advanced liver disease. High expression of GP73 can be detected in liver cell fusion giant cells of adult cytomegalovirus hepatitis (GCH) patients. GP73 is generally expressed in epithelial cells of the bile duct, rather than in liver cells.