Researchers have identified more than 1,100 proteins from various organs in saliva, providing a lens through which they can view your entire body. "People don't realize that the salivary glands are connected to the rest of the body's organs via the bloodstream and nervous system, and when our liver or pancreas is not in a normal state, our saliva will reflect that," says David Wong, an associate dean of research at the UCLA School of Dentistry and editor of the first book on the subject, to be published later this year, Saliva Diagnostics. For the past five years, Wong and his research team have been unlocking the secrets of spit, and along the way they've developed a test for oral cancer and are in the process of creating ones for pancreatic, lung, breast, and ovarian cancer. Their oral cancer test is the closest to being ready for an FDA review.
Other labs have been making strides as well: Earlier this year, Charles Streckfus, DDS, a professor of diagnostic sciences at the University of Texas in Houston, published research in which he found breast cancer–related proteins in saliva; Joseph A. Califano, MD, heads up a team at Johns Hopkins studying a swish-and-spit test for head and neck cancer.
The saliva test is appealing because people visit dentists more frequently than their doctor, and the screens will be relatively inexpensive. Though the technology is still at least five years away, researchers are nonetheless enthusiastic. "The earlier you can detect disease, the more likely you are able to cure it, which is why these tests could have a major impact," says Lawrence Tabak, DDS, PhD, director of the National Institute of Dental and Craniofacial Research, a government agency that funds much of the current research.