VEGFA and cancer: However, recent studies in cancer stem cells (CSCs) provided additional insight into tumor angiogenesis [3], as accumulating data have indicated that CSCs are involved in tumor angiogenesis not only by enhanced capacity of vascular endothelial growth factor (VEGF) secretion compared to its counterparts [4], but, more strikingly, they are strongly proangiogenic and can generate “CSC-derived endothelial progenitor cells” [5, 6].