CSPG4 and neoplasm: Additionally, since tumor vessels - in contrast to normal vessels - show a leaky and permeable endothelial cell lining [16–19] which allows for extravasation of larger molecules into the tissue [20, 21] and because NG2 is expressed on pericytes covering the abluminal surface of endothelial cells, this could constitute a second barrier for selectivity leading to tumor vessel infarction induced by tissue factor (TF) retargeted to NG2 (Figure 1).