Validation of antiangiogenic drugs with hAR assays. (A) hARs treated with antiangiogenic drugs. Quantification of angiogenic outgrowth at 15 days of culture in EGM-2. hARs treated with indicated concentrations of Sunitinib, SU5416, PI-103, Avastin, and anti-VEGF Ab. For Combretastatin, a vascular-disrupting agent, the treatment started at day 19 (shown in supplemental Figure 6B). Values shown are box-and-whisker plots, normalized to the median of DMSO or control IgG-treated hARs, of 3 independent experiments, each from 6 different umbilical cords (*P < .05 vs DMSO or control [ctr] IgG hARs; **P < .01; ***P < .001). (B) Evaluation of IC50 of antiangiogenic drugs on human and mAR assays. Nonlinear regression R2 > 0.7.