CD248 and neoplasm: However, later work by us and others revealed that endosialin is not a marker of angiogenic endothelial cells, but rather a marker of activated pericytes and tumor stromal myofibroblasts (Rettig et al, 1992; St Croix et al, 2000; MacFadyen et al, 2005, 2007; Christian et al, 2008; Simonavicius et al, 2008).