Figure 1.

Two different contexts for the delivery of nanomedicines: solid tumor vs. the blood circulation. In a solid tumor, nanomedicine migrates to the tumor through leaky tumor-associated vasculature where dysfunctional lymphatic drainage enables accumulation of nanomedicine in the tumor. In contrast, once cancer cells are shed into the blood circulation to form CTCs, they are subjected to environmental changes such as shear stress, abundant RBCs and plasma proteins, and interactions with platelets, endothelial cells and other vascular components