May 22, 2013
Detecting Prostate Cancer In Urine
Lee Rannals for redOrbit.com — Your Universe Online
University of California, Irvine researchers recently wrote in the Journal of the American Chemical Society that they have found a safe and inexpensive way to identify clinically usable markers for prostate cancer in urine.
“Our goal is a device the size of a home pregnancy test priced around $10. You would buy it at the drugstore or the grocery store and test yourself,” said Reginald Penner, UC Irvine Chancellor´s Professor of chemistry and co-author of the study. “We´re on the verge of a very important breakthrough in a new era of personal health management.”
A recent report found that a prostate-specific antigen (PSA) test can be more harmful than beneficial. About 240,000 men in the US are diagnosed with prostate cancer every year, and 29,000 are expected to die from it in 2013.
“A big problem is that the approach used now does not catch cancer soon enough,” said co-author Gregory Weiss, a UC Irvine biochemist. “We want this to be a disruptive technology that will change how we save lives and that will bring down healthcare costs drastically.”
The team was able to create an early screening test by using a combination of readily available chemicals and unique electronic sensors. Salt in urine helps conduct electricity, but it also makes it challenging for typical biosensors to differentiate "signals" from cancer molecules. The team developed a new sensor by adding nanoscale protein receptors to tiny, pencil-like viruses called phages that live only within bacteria.
“We add a high concentration of the viruses, and they get trapped directly in the electrode. We´re jamming the signal with the cancer marker, and it stays on louder than all the other material,” said lead author Kritika Mohan, a graduate student with Weiss´ lab.
“To our surprise, it works really well in the ingredients that make up urine.”
Weiss said the receptors are incredibly tough and don't need to be refrigerated. He also said they are grown in a yeasty, broth solution that could easily be mixed on an industrial scale.
“The manufacturing costs would be low, because the material costs are very, very low. The receptors for recognizing the cancer markers are really inexpensive to make. That´s why we chose these viruses,” Weiss explained.
The American Urological Association (AUA) introduced new clinical practice guidelines for screening prostate cancer earlier this month. The agency said that prostate cancer tests are "not recommended" for anyone under the age of 40 or over the age of 70.
“There is general agreement that early detection, including prostate-specific antigen screening, has played a part in decreasing mortality from prostate cancer,” added Dr. H. Ballentine Carter, chairman of the panel that developed the new guidelines. “It´s time to reflect on how we screen men for prostate cancer and take a more selective approach in order to maximize benefit and minimize harms. “¦ The best available evidence suggests that following these guidelines will lead to an improved benefit-to-harm ratio.”