VEGFA and neoplasm: Second, at the molecular level, the PPE-1 promoter is activated by VEGF, and lack of VEGF reduces PPE-1–3x promoter-regulated transgene expression and prevents VB-111 activity.21 Third, at the tissue level, VB-111 acts by disrupting angiogenic blood vessels, which promotes tumor starvation but also enables immune cell penetration, while bevacizumab triggers the closure of the blood–brain barrier and may prevent VB-111-mediated recruitment of immune cells into the CNS.