Abstract A study in mice indicates that the adhesion molecule P-selectin, which is expressed on the endothelium during inflammation, may serve as a target for the delivery of drug-filled nanoparticles to tumors. Antitumor efficacy was achieved in several mouse models of cancer, and the researchers successfully used this approach even against noninflammatory tumors, by first using ionizing radiation to trigger P-selectin's expression on the tumor vasculature.