PECAM1 and neoplasm: identified that OX40 ligand–Fc fusion protein (OX40L‐Fc), a novel tumor necrosis factor receptor family member, promoted anti‐tumor activity in most mice by rendering the tumor microenvironment permissive to type 1 T‐cell infiltration and increase of vascular cell adhesion molecule (VCAM‐1) and CXCL9 expression, upregulated by CD31+ vascular endothelial cells 112.