VEGFA and breast cancer: Apart from suppressing VEGF expression and hypoxia inducible factor 1α (HIF-1α) signaling in breast cancer cells [273], studies analyzing the effects of vitamin D on tumor angiogenic processes revealed the direct effects of calcitriol or its analogs on tumor-derived endothelial cells [274] or VEGF-induced bovine aortic endothelial cells [162].