PDPN and cancer: D2-40 is a commercially available mouse monoclonal antibody against human podoplanin, which is a mucin-type transmembrane protein in lymphatic endothelial cells[13].The antibody is a highly specific marker for lymphatic endothelium and has proven valuable in distinguishing lymph vessels from blood vessels and in detecting lymphatic invasion in various malignant neoplasms[11], [14], [15].In the present study, D2-40 staining was mainly detected in lymphatic endothelial cells, while tumor cells and blood vessels exhibited no staining (Figure 1B and 1C).