Even the safety of animals stands to get a boost from testing circulating DNA. Researchers last month announced that chronic wasting disease in elk and bovine spongiform encephalopathy (mad cow disease) in cattle could be diagnosed up to six months before symptoms show up.
The only way to confirm a case of these diseases right now is to examine an animal's brain postmortem, says study leader Christoph Sensen, director of the Sun Center of Excellence for Visual Genomics at the University of Calgary in Alberta. But by comparing the circulating DNA profiles of sick and healthy animals, Sensen's team was able to identify disease-specific genetic patterns for diagnostic use in live animals. Providing a cheap method for testing all livestock in slaughterhouses, Sensen says, will be important for certifying the safety of meat exports and preventing future disease transmission to humans.
Although blood has been the primary focus for work on circulating nucleic acids, some researchers are now looking to test other bodily fluids. Urine is a particularly attractive candidate as it could provide an alternative source for testing circulating DNA and RNA in the developing world where drawing blood can be impractical, notes Timothy Block, co-founder of the Hepatitis B Foundation and a virologist at the Drexel University College of Medicine in Philadelphia.
With such broad applications, King's College's Butt agrees that the future of this technology is bright, but cautions that commercial partners will be key for developing clinical tests in the coming years.
Howard Urnovitz, CEO of Chronix Biomedical, Inc., in San Jose, Calif., is already looking for companies in the diagnostic field to help commercialize his company's bioinformatic approach to computationally mining thousands of sequenced circulating DNA fragments from healthy volunteers and patients for diagnosing and tracking specific diseases, including multiple myeloma (a cancer of disease-fighting plasma cells that is incurable but treatable), breast cancer and multiple sclerosis.
Despite the pressing need for identifying and validating new disease markers, Peter Gahan, a cell biologist at King's College, is optimistic. "Funding was virtually nonexistent five to 10 years ago," Gahan says, but "we are already beginning to get markers that could enter into predictive medicine."