VEGFA and cancer: The formation of the immunosuppressive microenvironment involves immunosuppressive cytokines (such as vascular endothelial growth factor (VEGF), transforming growth factor-β (TGF-β), galectin, or indoleamine 2,3-dioxygenase (IDO)] released by cancer cells; these cytokines block the maturation of immune cells and promote the recruitment of immunosuppressive cells (57).