VEGFA and acute myeloid leukemia: BM-mediated chemoprotection can be promoted by several cell types, including cancer-associated fibroblasts (CAF), -through the release of growth differentiation factor 15 [69], activator of TGF-β signaling in chemo-resistant leukemic cells [70]-, and endothelial cells, through the production of vascular endothelial growth factor (VEGF) and other adhesion molecules which trigger survival and proliferative pathways in AML cells [47].