VEGFA and neoplasm: CAFs can respond to hypoxia by upregulating hypoxia-induced angiogenesis regulator (HIAR), which in turn increases CAF motility and secretion of vascular endothelial growth factor A (VEGFA).20 This induces angiogenesis to improve tumour oxygenation, nutrient flow and waste removal, and the resultant decline in hypoxia stimulates further CAF activation.21 CAFs can also be influenced to stimulate a vessel-rich environment by tumour cells.