PDPN and cancer: A number of studies have revealed that a sialomucin type I transmembrane glycoprotein, podoplanin, regulates processes of cell migration, epithelial-to-mesenchymal transition (EMT), and tumor metastasis, as well as cell cycle and cell proliferation through extracellular matrix signaling, and is often related to tumor malignancy and poor outcome in many cancers including MPM [39]–[44].