Jinnin et al. showed that VEGFR1 reduction in hemangioma facilitated VEGF-dependent VEGFR2 signal activation, further stimulating the downstream pathways (primarily PI3K/Akt signaling pathway) and contributing to the proliferation of vascular endothelial cells and the formation of new vessels [57, 61]. The gene discussed is FLT1; the disease is hemangioma.