Spit Test

By Dan Gordon

Published Oct 1, 2006 12:00 AM

Studying saliva samples taken from oral cancer patients, Wong and colleagues identified messenger RNA biomarkers — molecules carrying genetic information in cells — that, when elevated, are predictive of the disease. They concluded that high levels of four cancer-associated messenger RNA molecules out of the 3,000 found in saliva create a signature that sets apart people with early cancers of the mouth, tongue, larynx and pharynx from healthy people.

In the test, a patient's saliva sample is measured for the four RNA biomarkers, and the result is a score that indicates within 24 hours whether the patient is at risk for oral cancer. If a larger study soon to be conducted across the country confirms the UCLA results, the oral cancer spit test will move a giant step closer to reality.

Wong and colleagues also plan to explore the potential for finding salivary biomarkers that might result in spit tests for breast and pancreatic cancers, type 2 diabetes and Alzheimer's disease. "Now that we have proved the concept that saliva can contain important clinical information for oral cancer, the next question is to see whether diseases outside the mouth can be revealed in the saliva," he says. Wong suspects that they can, citing studies that have shown that certain biomarkers move from the blood to the saliva.

Wong sees a future in which all dentists are equipped with spit detectors to diagnose diseases. "It may seem like science fiction now," he says, "but one day we may be able to use saliva to tell us not only that an individual has cancer, but the best way to treat that person according to her genetic makeup as expressed in her spittle."

The Facts About Oral Cancer

Approximately 30,000 people will be diagnosed this year with cancer of the mouth and/or part of the throat. Most oral cancers can be traced to tobacco and alcohol use.

Only half of those diagnosed with oral cancer survive five years. Because the disease spreads quickly, the key is early detection.

Early symptoms include persistent changes in the mouth or throat, such as sores, swelling or numbness, and difficulty eating or swallowing. The disease is often detected by dentists during regular visits.

Strategies to lower the risk of oral cancer include avoidance of tobacco products, drinking alcohol in moderation if at all, using lip balm that contains sunscreen, and eating the five daily servings of fruits and vegetables recommended by the National Cancer Institute.

For more information on oral cancer, visit the National Institute of Dental and Craniofacial Research's Web site at www.nidcr.nih.gov. To get inside information on healthy mouths, check out the School of Dentistry's Web site at http://uclasod.dent.ucla.edu.