{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"CD31 is also called PECAM-1 for platelet endothelial cell-adhesion molecule. It plays a key role in removing aged neutrophils from the body. CD-31 is normally found on stem cells, endothelial cells, platelets, macrophages and Kupffer cells, granulocytes, T/NK cells, lymphocytes, megakaryocytes, fibroblasts, osteoclasts and neutrophils. CD-31 is also expressed in certain tumors, including Epithelioid Hemangioendothelioma, Epithelioid Sarcoma like Hemangioendothelioma, other vascular tumors, Histiocytic malignancies, and Plasmacytomas. It is rarely found in some sarcomas and carcinomas. CD-31 and macrophages play a key role in tissue regeneration."}]},{"type":"paragraph","children":[{"type":"text","value":"CD31 is widely used to identify the vascular origin of neoplasms, as it is a highly specific and sensitive marker for vascular endothelial cells."}]}]}