We recently demonstrated that TNFα increases the surface expression of α5β1 on HUVEC [62], and together with data showing that ligation of integrin α5β1 promotes tumor angiogenesis [63] and α5-null carcinomas exhibit reduced blood vessel formation [64] it is tempting to speculate that ICAM3+ naEFCs bind to activated endothelium via α5β1 to promote vascular development. Here, ICAM3 is linked to carcinoma.