To overcome this problem, some groups have attempted to mix different ligands to enhance the targeting ability of the NPs; for example, some researchers have conjugated RGD and folate (to target the folate receptor, which is overexpressed in many tumor cells) together [214] or have used an anti-vascular endothelial growth factor (VEGF) aptamer together with RGD on NPs [215]. This evidence concerns the gene VEGFA and neoplasm.