Our results demonstrating an antiangiogenic effect of RXDX-105 in immunocompromised mouse models, however, suggest that RET, and possibly the RAS-MAPK pathway, may play previously undescribed roles in neuroblastoma tumor angiogenesis, although direct antiangiogenic effects of EphA2 inhibition, in addition to inhibition of VEGFR1 and VEGFR2, also cannot be completely ruled out at the concentrations likely achieved in our mice treated with RXDX-105. Here, FLT1 is linked to neuroblastoma.