Pdpn was discovered for the first time in rat and mice lungs, and on the surface of stromal cells in lymph nodes (LNs) in mice, which has been found to be expressed in a wide variety of cells later, such as lymphatic endothelial cells, tumor cells, osteocytes, choroid plexus epithelial cells, glial cells, and cancer-associated fibroblasts for its pleiotropic functions (7, 22). The gene discussed is PDPN; the disease is cancer.