Earlier this month the health news was dominated by seismic shifts in the safety of hormone replacement therapy. Now it seems like everywhere I turn I'm finding new information on prostate cancer. I don't want to hit you over the head with this subject, but this weekend I came across a report that's a perfect follow up to the study I told you about last week that demonstrated how the misreading of prostate specific antigen (PSA) levels may be responsible for the significant overdiagnosis of prostate cancer ("Under the Knife; Under the Gun" 7/23/02).
For the moment, imagine you're sitting out on your porch one of these warm evenings watching your children or grandchildren run around the yard chasing fireflies. Without fail, one of them will come to you with their hands cupped to show you the firefly they've just captured. You probably would never imagine that one of the tools that may completely revolutionize how prostate cancer is detected might be right there in the palm of your young one's hand.
It sounds like something you'd see in a Steven Spielberg film. Researchers from the Jonsson Cancer Center at UCLA have just released a report that explains how they created a way to literally light up prostate cancer cells and then find them with special imaging technology.
Their process developed in three steps. First they engineered a virus that recognizes the PSA protein that is only present in prostate cancer cells. In step two the researchers attached luciferase (the substance that creates the glow in fireflies) to the virus which then was injected into tumor-bearing laboratory mice. The virus in effect went looking for the prostate cancer cells, and the luciferase lit them up when they were found.
In the final step they used an advanced, non-invasive imaging technology to not only find illuminated cancer cells, but also to track them as they spread to the lungs and spine. With this imaging technique, the researchers were also able to spot the presence of cancer cells that were still not advanced enough to either trigger symptoms or be detected by conventional methods.
The UCLA team hopes that in the next step of their research they may be able to attach gene-based therapies to the virus so that they can target and treat only the prostate cancer cells. In a UCLA press release, lead author of the study, Lily Wu, said "The idea would be to deliver a toxic gene to the cancer that would not harm surrounding healthy cells."
Wu and her colleagues are also confident that it's only a matter of time before they're able to accomplish this same type of prostate cancer cell detection in humans. For human subjects, however, a different sort of imaging system will be required, so another team of researchers at UCLA is already developing the next generation of imaging technology, helped considerably by a $9.8 million grant, awarded by the National Cancer Institute.
So in the wake of last week's e-Alert about the overdiagnosis of prostate cancer, this study brings a hopeful note about one way that health providers may eventually overcome some of the dilemmas, though it looks like it will be a bit of a wait. We'll keep you posted on this new technology as we learn more.
To Your Good Health,
Jenny Thompson
Health Sciences Institute
Sources:
"Visualization of Advanced Human Prostate Cancer Lesions in Living Mice by a Targeted Gene Transfer Vector and Optical Imaging" Nature Medicine, 7/22/02
"Scientists at UCLA's Jonsson Cancer Center Develop Unique Tracking System That Seeks Out Prostate Cancer Metastases" UCLA Press Release, 7/22/02 |
