CD31

Platelet endothelial cell adhesion molecule (PECAM-1) also known as cluster of differentiation 31 (CD31) is a is_associated_with::protein that in humans is encoded by the PECAM1 is_associated_with::gene found on chromosome 17. PECAM-1 plays a key role in removing aged neutrophils from the body.

Function
PECAM-1 is found on the surface of is_associated_with::platelets, is_associated_with::monocytes, is_associated_with::neutrophils, and some types of is_associated_with::T-cells, and makes up a large portion of endothelial cell intercellular junctions. The encoded protein is a member of the is_associated_with::immunoglobulin superfamily and is likely involved in is_associated_with::leukocyte transmigration, is_associated_with::angiogenesis, and is_associated_with::integrin activation.

Tissue distribution
CD31 is normally found on endothelial cells, platelets, macrophages and Kupffer cells, granulocytes, T / NK cells, lymphocytes, megakaryocytes, osteoclasts, neutrophils.

CD31 is also expressed in certain tumors, including epithelioid hemangioendothelioma, epithelioid sarcoma-like hemangioendothelioma, other is_associated_with::vascular tumors, histiocytic malignancies, and plasmacytomas. It is rarely found in some sarcomas, such as is_associated_with::Kaposi's sarcoma,   and carcinomas.

Immunohistochemistry
In is_associated_with::immunohistochemistry, CD31 is used primarily to demonstrate the presence of endothelial cells in histological tissue sections. This can help to evaluate the degree of tumour is_associated_with::angiogenesis, which can imply a rapidly growing tumour. Malignant endothelial cells also commonly retain the antigen, so that CD31 immunohistochemistry can also be used to demonstrate both is_associated_with::angiomas and is_associated_with::angiosarcomas. It can also be demonstrated in small lymphocytic and is_associated_with::lymphoblastic lymphomas, although more specific markers are available for these conditions.