Platelet Endothelial Cell Adhesion Molecule 1 (PECAM1) is a single-pass membrane receptor also known as CD31 (cluster of differentiation 31.) CD31 is expressed at high levels at endothelial cell junctions, and therefore the CD31 antibody is widely used as an endothelial marker, one use being to measure the progression of angiogenesis following recurrence of tumors.
