CD248 and neoplasm: Ontuxizumab (MORAb-004) is a mAb directed against the C-type lectin transmembrane receptor endosialin (or tumor endothelial marker-1 TEM-1 or CD248), which is commonly found on the surface of mesenchymal cells of tumor microenvironment, including tumor endothelium, tumor-associated pericytes and activated fibroblasts, which are thought to play a key role in the development of tumor neovascular networks, cell–cell adhesion, stromal interaction and host defense.