21 May 2010
Vol 328, Issue 5981

About The Cover

Cover image expansion

COVER Tumor-penetrating transport of cancer drugs is activated by the peptide iRGD (multicolored ring), which binds to integrin receptors (blue and yellow) in tumor blood vessels, and is subsequently cleaved. The cleaved peptide then binds to neuropilin-1 receptors (purple), activating a transport system that carries coadministered drugs, such as antibodies (green), deeper into tumor tissue. See page 1031. Image: Peter Allen/University of California, Santa Barbara