Early detection is extremely important for the treatment of many cancers and screening based on imaging techniques has been a major contributor to the cause. Scans like MRI and PET provide non-invasive methods, but with both advantages and shortcomings: MRI offers higher spatial resolution, for instance, but low sensitivity to the tracers, or contrast agents, needed to visualize a tumor inside the patient’s body. The Ruoslahti lab at Sanford Burnham Prebys Medical Discovery Institute has developed a new method of locating tumors with MRI—one inspired by the body’s own clotting action and which is able to amplify its own action.
Linking a peptide that binds specifically to clots in tumor vessels (and not in healthy tissue) with a well established contrast agent, the researchers created nanoparticles that can drive additional clotting at the tumor site, thus drawing even more of the MRI tracer where it is needed. The body’s platelets operate in a similar way, accumulating and amplifying their presence at the disease location. For the case of MRI scans, the Ruoslahti team has established its proof-of-concept in vivo. The tracer-peptide combination has proven to be non-toxic, greatly enhances the imaging of tumors and is highly selective in homing to tumor tissue only.
Image credit: Hellerhoff - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=10323803