TWEAK (otherwise known as TNFRSF12A, Tumor necrosis factor receptor superfamily member 12A), is a member of the TNF family and was first described as a weak inducer of apoptosis in some cell types. It is thought to promote angiogenesis and the proliferation of endothelial cells as well as modulating cellular adhesion to matrix proteins. Recently, a receptor for TWEAK was isolated by expression cloning from a HUVEC cell cDNA library.