Biolegend, 593209, Recombinant Human Mesothelin (ELISA Std.)

Human mesothelin, also known as CAK1 and MSLN, is a cell-surface protein that is expressed on normal mesothelial cells lining the pleura, pericardium, and peritoneum. It is expressed as a 70 kD pre-cursor protein with a furin cleavage site, which produces two products: 1) megakaryocyte potentiating factor (MPF) (30 kD) and 2) mesothelin (40 kD). MPF is a cytokine that is released. Mesothelin, for the most part, is membrane-bound by a glycosylphosphatidylinositol linkage and has three glycosylation sites. Soluble mesothelin is believed to result from proteolytic cleavage to release it from the membrane linkage, or from alternative splicing of the mesothelin gene. The normal function of mesothelin is not known. Mice knockouts produced no obvious phenotypes with normal growth and reproductive parameters. However, mesothelin is overexpressed by cancer cells, particularly in mesotheliomas, ovarian adenocarcinomas, pancreatic adenocarcinomas, and squamous cell carcinomas, and lung cancers. It binds to MUC16/CA-125, which is a cell surface mucin and ovarian cancer biomarker, and has been speculated to be involved in peritoneal dissemination of ovarian cancer cells. Mesothelin has also been shown to be elevated in the serum of cancer patients compared to normal patients. As such, it has become the focus of cancer research in the areas of diagnostics, immunotherapy, and cancer vaccinology. For example, SS1P is a recombinant immunotoxin which targets mesothelin-expressing cancer cells. Its anti-mesothelin Fγ domain confers specificity, while its Pseudomonas exotoxin domain results in cell death. This potential drug has already finished Stage I clinical trials.