Oral cancer is the 6th most common cancer in men and the 14th most common cancer in women. In the US, oral cancer will be diagnosed in an estimated 30,000 Americans this year and will cause more than 8,000 deaths. The disease kills approximately one person every hour. Oral cancer can spread quickly. The majority of oral cancers are diagnosed in late stages, which accounts for the high death rates. Only half of those diagnosed with the disease will survive more than five years. However, if the cancer is detected early, there is an 80 to 90% chance for survival. It is therefore extremely important to detect oral cancer as early as possible, when it can be treated more successfully, thus enhancing the rate of survival.
Currently, the early detection of oral cancer depends on a thorough oral cancer examination, usually by a dentist or other qualified health care provider, for possible signs and symptoms of this disease. Scientists are working on technologies and biomarkers for the early detection of oral cancer. Saliva, an easy-to-obtain and non-invasive body fluid, has recently been shown to harbor highly informative biomarkers for oral cancer detection. Scientists in Dr. David Wong’s laboratory at the School of Dentistry at UCLA have discovered that seven RNAs, molecules that carry information in cells, when found in saliva are very useful for oral cancer detection. The saliva oral cancer RNA signature has been tested in over 300 saliva samples from oral cancer patients and healthy people, and the signature is always present in higher levels in the saliva of oral cancer patients than in saliva from healthy people, with an overall accuracy rate of about 85%.
The next important step was to turn these scientific findings into clinical tests that can be used for early oral cancer detection. Wong’s research team reported at the 35th Annual Meeting of the American Association for Dental Research for the first time that they have developed a standardized “Saliva RNA Test for Oral Cancer” ready for clinical usage.
The “Saliva RNA Test” has been tested in 100 oral cancer and healthy people, and it has been confirmed that four saliva oral cancer RNA biomarkers are highly accurate in detecting oral cancer, at around 82%. This is the first standardized saliva-based test for clinical oral cancer detection and will have enormous clinical value in reducing the mortality and morbidity for oral cancer patients, as well as improving their quality of life.
In a related study, further illustrating the importance of saliva as a diagnostic tool, scientists at the National Institute of Dental and Craniofacial Research (NIDCR), one of the Federal Government’s National Institutes of Health (NIH), have studied the protein profile in the saliva of patients with Sjögren’s syndrome, an autoimmune disorder in which the immune system cells attack the saliva- and tear-producing glands, causing them to become inflamed. Patients suffer from constant dryness of the mouth and eyes, as well as many other systemic problems. In this recent study, the scientists analyzed saliva from patients with and without Sjögren’s syndrome to find out whether the amounts and types of salivary proteins differed. They found that saliva from the patients with Sjögren’s has both increased amounts of proteins related to inflammation and a decreased amount of proteins produced by salivary glands. Future studies are planned to determine whether these protein levels could be useful in diagnosing Sjögren’s syndrome.
This is a summary of abstract #218, “Salivary Oral Cancer Transcriptome Biomarkers (SOCTB) for Clinical Detection”, by J. Wang, S. Henry, T. Yu, Y. Li, D. Elashoff, M. Oh, K.-C. Li, X. Wei, and D. Wong (UCLA), and abstract #219, “Salivary Biomarkers in Parotid Saliva of Sjögren’s Syndrome”, by J.C. Atkinson, O. Ryu, G. Hoehn, G. Illei, and T. Hart (NIDCR/NIH, Bethesda, MD), to be presented at 11:30 a.m. and 11:45 a.m., respectively, on Thursday, March 9, 2006, in No. Hemisphere A-1 of the Walt Disney World Dolphin Hotel, during the 35th Annual Meeting of the American Association for Dental Research.