KDR and neoplasm: Numbers of circulating EPCs (defined as peripheral blood MNCs positive for both CD34 and VEGFR2 but negative for CD45 [34]) were significantly elevated in tumor bearing mice, but not in deguelin-treated tumor bearing mice (Figure 4C), suggesting that low dose deguelin (2 mg/kg) inhibits tumor growth by suppressing vasculogenesis through inhibition of EPC mobilization from BM into circulating blood.