The innovation could save many lives

Feb 17, 2010 11:40 GMT  ·  By

Scientists at the University of California in San Diego (UCSD), and the Moores UCSD Cancer Center, announce the development of a new type of fluorescent probe. The structure is capable of affixing itself to cancer tumors specifically, evidencing them under certain lighting conditions. The new work was constructed on previous research conducted by team leader Roger Tsien, PhD, who is a professor of pharmacology, chemistry and biochemistry at UCSD, and also a Howard Hughes Medical Institute investigator. He is also the winner of the 2008 Nobel Prize in Chemistry, for developing the green fluorescent protein (GFP) marker, PhysOrg reports.

The new biological probes developed at the university were tested on unsuspecting lab mice. Experiments revealed that these structures were capable to sticking directly to tumors in the rodents, and immediately light them up for observers to see. This in turn allowed the investigators to not only observe the tumor that appeared in other imaging techniques as well, but also to discover new, hidden cancer tissue, that was not targeted by specific drugs. The mice that were surveyed with the probes survived 500 percent more often than those who were investigated using regular means.

“The development of biological probes that can guide surgeons, rather than depending only on feel and normal 'white light' to see, can provide tools to navigate the body on a molecular level,” explains UCSD School of Medicine assistant professor of surgery Quyen Nguyen, MD, PhD, who is also the first author of the study. Details of the groundbreaking work appear in the February 15 early edition of the journal Proceedings of the National Academy of Sciences (PNAS). In addition to bringing the prospect of using molecular tools in the surgeries of the future, the new work will also soon allow surgeons to outline the actual contours of tumors in real-time, as they are performing extrication procedures.

The new probes, carrying fluorescent and magnetic tags, are delivered inside the body using synthetic molecules called activatable cell penetrating peptides (ACPPs), as well as a host of nanoparticles. This allows for the markers to be delivered precisely at the site of the tumor, which thus becomes visible under MRI. Scientists say that this could minimize the risk of surgeons living behind traces of the tumor. This is not at all uncommon, especially when handling the edges of a group of cancer cells. At this point, doctors conducting operations relay on experience and feel to remove tumors, but they can sometimes miss some cells, which will later increase the risk of cancer reoccurring.