We found that TR3/Nur77 is highly and transiently up-regulated in cultured endothelial cells (EC) and during angiogenesis in vivo. TR3 is induced by angiogenic factors having microvessel permeable activity, including VEGF, histamine and serotonin, but not by angiogenic factors that do not have microvessel permeable activity, including bFGF, PlGF and PDGF [15-17], and in postnatal angiogenesis, such as tumor angiogenesis and skin wound healing [16, 29]. Here, NR4A1 is linked to neoplasm.