PDPN and cancer: For example, the transmembrane protein podoplanin (PDPN) is highly expressed on Th17 cells and acts as a negative regulator of Th17 pathogenicity.243 Mice with a selective depletion of PDPN in T cells show enhanced EAE severity with increased T-cell infiltration into the CNS.244 Interestingly, PDPN was also identified as an important regulator in cancer.