To date, several biomarkers have been reported to be useful in diagnosing mesothelioma, including cytokeratin 19 fragment 5, tissue polypeptide antigen 5,6, hyaluronan 6,7, carbohydrate antigen 125 6,8, osteopontin 9,10, and soluble mesothelin-related protein (SMRP) 11–14. Here, MSLN is linked to mesothelioma.