getting cancer to declare itself (and detect its extent) using fluorescentce

[Lani]

Molecular probe 'paints' cancer cells in living animals, Stanford researchers find [Stanford School of Medicine]
STANFORD, Calif. — Researchers at the Stanford University School of Medicine have developed a molecular probe that sets aglow tumor cells within living animals. Their goal is to use the probe to improve the diagnosis and treatment of cancer and other diseases.
The probe's main ingredient is a molecule that labels active proteases—protein-destroying enzymes—that run amok in cancerous cells. The molecule is normally invisible to the naked eye but it carries a fluorescent tag that lights up when it binds to the protease. The tag beams out near-infrared light that passes through skin and is detectable with a special camera. The use of the imaging technique in mice is described in a study published in the Sept. 9 advance online issue of Nature Chemical Biology.
"Nowadays the detection of cancer, breast cancer for instance, is normally done by mammography, using X-rays—which might actually increase your risk of cancer. We think these probes may ultimately provide a less harmful, noninvasive method of detecting cancer," said the article's lead author Galia Blum, PhD, a postdoctoral scholar in the laboratory of Matthew Bogyo, PhD, assistant professor of pathology.
And that's just for starters.
"It's neat. The next generation of our experiments will apply the probes during surgery," said Bogyo, the study's senior author. "It would be nice to 'paint' it on tissues so you could distinguish between tumor and non-tumor."

ABSTRACT: Noninvasive optical imaging of cysteine protease activity using fluorescently quenched activity-based probes [Nature: Chemical Biology]

We have generated a series of quenched near-infrared fluorescent activity-based probes (qNIRF-ABPs) that covalently target the papain-family cysteine proteases shown previously to be important in multiple stages of tumorigenesis. These 'smart' probes emit a fluorescent signal only after covalently modifying a specific protease target. After intravenous injection of NIRF-ABPs into mice bearing grafted tumors, noninvasive, whole-body imaging allowed direct monitoring of cathepsin activity. Importantly, the permanent nature of the probes also allowed secondary, ex vivo biochemical profiling to identify specific proteases and to correlate their activity with whole-body images. Finally, we demonstrate that these probes can be used to monitor small-molecule inhibition of protease targets both biochemically and by direct imaging methods. Thus, NIRF-ABPs are (i) potentially valuable new imaging agents for disease diagnosis and (ii) powerful tools for preclinical and clinical testing of small-molecule therapeutic agents in vivo