Figure 1. Schematic of nanomedicine deposition by passive and/or active targeting in the presence or absence of an observable EPR effect (leaky vasculature).

Left: Passive targeting of non-ligand targeted nanomedicines results in delivery and a biologic effect. Center: Passive targeting of an actively targeted nanomedicine results in enhanced delivery and improved biologic effect. Right: Active targeting of a nanomedicine in the absence of leaky vasculature results in marginalization of nanomedicines without delivery into the tumor microenvironment resulting in no biologic effect.