ANXA2 and glioblastoma: Importantly, tumor exosomes contain key pro-angiogenic factors directly linked to endothelial cell migration and the induction of new blood vessel formation, such as Vascular Endothelial Growth Factor (VEGF), overexpressed in the majority of tumors [82,83], Epidermal Growth Factor like domains (EDIL-3/Del1) in bladder cancer cell-derived exosomes [84] and Annexin A2 (ANXA2), one of the most abundant proteins of glioblastoma cell-derived exosomes [85].