Importantly, recent evidence shows that ITLN1 is over-expressed in human malignant pleural mesothelioma (MPM) and secreted into pleural effusions, and serves as a biomarker for distinguishing MPM from lung cancer [17, 18], implicating the emerging roles of ITLN1 in human cancers. Here, ITLN1 is linked to malignant pleural mesothelioma.