VEGFA and neoplasm: The critical role of Tie2high/VEGFhigh macrophages in TMEM doorway function was further demonstrated by the conditional ablation of macrophages in PyMT transgenic mice and by VEGF deletion in the monocyte/macrophage lineage in FVB mice; in both cases, there was a dramatic inhibition of TMEM function and, consequently, of tumor cell intravasation and metastasis formation [71,77].