CSF1R and neoplasm: As CSF-1R signaling regulates macrophage VEGF-A secretion, and macrophage-secreted VEGF-A is required for vascular opening at TMEM doorways [10], we examined the role of the CSF-1R in mediating vascular opening and tumor cell intravasation at TMEM doorways in vivo, as defined in Fig. 1 and previously [6].