DLL4 and neoplasm: We observed that tumors with Dll4+/− BM-VPC had significantly lower FN1 content (Figure 6A) in the vessels and these had significantly less pericyte coverage, suggesting these would likely be more unstable (the PECAM/SMA ratio of the tumors is shown in Figure 6B; the higher the ratio the less pericyte/SMA coverage of tumor vessels).