The product also has potential as a research aid. Michael Zalefsky, a radiational oncologist at Memorial Sloan-Kettering Cancer Center in New York and another investigator in the clinical trial, does research on radiational-seed implants for prostate cancer. "As we learn more about [the Aposense tracer], it may help us predict how sensitive the tumor cells are to the particular treatment that we are utilizing," he says. "It has a lot of great potential benefit, but all this needs to be explored in prospective studies."

Because the characteristics of apoptotic cells are universal, Aposense says that its tracer might also be used to investigate other ailments. In neurology, the company's researchers believe, the tracer could be used to image damage from a stroke; in cardiology, it might identify areas of blood vessels with unstable atherosclerotic plaque; in organ transplantation, it might identify rejection at its earliest stages.

But the technology still has a long way to go to prove itself, and some worry that Aposense may be getting ahead of itself. Francis Blankenberg, an associate professor of radiology and pediatrics at Stanford University who has been working to develop a competing apoptosis-imaging technology, has been following the company's progress for a long time. He's unconvinced that the tracer molecule works as described and notes that he has not seen the mechanism they describe proven to his satisfaction.

Whether Aposense's marker is effective in cancer treatments should be established soon enough. The company hopes to complete its phase II trials with somewhere between 90 and 100 patients this year, and aims to have a larger, phase III trial concluded by 2012. Ashery hopes the results will herald a new era in personalized cancer treatments. "When you're trying to predict the response of a patient before treatment, you need to account for many variables," he says. "What we're providing is a way to see the effects of therapy in vivo. We can do this repeatedly in patient during treatment, and that offers an opportunity to individualize treatment."