PDPN is highly expressed in various intractable tumors, such as lung cancer, malignant mesothelioma, malignant brain tumors, and esophageal cancer; however, it is also known to be expressed in normal cells, including lymphatic endothelial cells, alveolar epithelial cells, skin basal cells, and renal epithelial cells. This evidence concerns the gene PDPN and lung cancer.