Mesothelin,C-ERC/mesothelin is a 40-kD a cell surface glycoprotein that is normally present on normal mesothelial cells lining the pleura,peritoneum,and pericardium.Moreover,mesothelin has been shown to be overexpressed in several human cancers,including virtually all mesothelioma and pancreatic cancer approximately 70% of ovarian cancer and extra bile duc cancer,and 50% of lung adenocarcinomas and gastric cancer.The full-length human mesothelin gene encodes the primary product,a 71-k Da precursor protein.The71-kD a mesothelin precursor is cleaved into two products40-k Da C-terminal fragment that remains membranebound via glycosylphosphatidylinositol anchor,and a31-kD a N-terminal fragment,megakaryocyte potentiating factor,which is secreted into the blood.The biologica functions of mesothelin remain largely unknown However,results of recent studies have suggested tha the mesothelin may play a role of cell proliferation and migration.In pancreatic cancer,mesothelin expression was immunohistochemically observed in all cases,bu absent in normal pancreas and in chronic pancreatitis Furthermore,the expression of mesothelin was correlated with an poorer patient outcome in severa human cancers.The limited mesothelin expression in normal tissues and high expression in many cancers makes it an attractive candidate for cancer therapy.The present review discusses the expression and function o mesothelin in cancer cells and the utility of mesothelin as a target of cancer therapy. Mesothelin, C-ERC / mesothelin is a 40-kD a cell surface glycoprotein that is normally present on normal mesothelial cells lining the pleura, peritoneum, and pericardium. Moreover, mesothelin has been shown to be overexpressed in several human cancers, including virtually all mesothelioma and pancreatic cancer approximately 70% of ovarian cancer and extra bile duc cancer, and 50% of lung adenocarcinomas and gastric cancer. The full-length human mesothelin gene encodes the primary product, a 71-k Da precursor protein. The71-kD a mesothelin precursor is cleaved into two products 40-k Da C-terminal fragment that remains membranebound via via glycosylphosphatidylinositol anchor, and a31-kD a N-terminal fragment, megakaryocyte potentiating factor, which is secreted into the blood. The biologica functions of mesothelin remain substantial unknown However, results of recent studies have suggested tha the mesothelin may play a role of cell proliferation and migration. In pancreatic cancer, mesothelin expression was immuno histochemically observed in all cases, bu absent in normal pancreas and in chronic pancreatitis Furthermore, the expression of mesothelin was correlated with an poorer patient outcome in severa human cancers. The limited mesothelin expression in normal tissues and high expression in many cancers makes it an attractive candidate for cancer therapy. The present review discusses the expression and function o mesothelin in cancer cells and the utility of mesothelin as a target of cancer therapy.