Laboratory News

Advances in Salivary Diagnostics Point to New Ways to Detect Cancer and Other Diseases

Diagnostic testing using saliva is becoming a reality and should be on the radar of clinical laboratories in the United States. Two recent advances in the field point to wider use of saliva specimens in laboratory testing. The first is the steady growth in recent years in the use of saliva in testing for oral diseases. Second, the Salivaoimics Knowledge Base (SKB), an in silico (performed on a computer or via computer simulation) saliva diagnostic atlas launched on April 6, 2008 during the 37th Annual Meeting of the American Association for Dental Research in Dallas, Texas.

Dentists may be first to use salivary diagnostics in a point-of-care (POC) setting. Last year, researchers unveiled the "IMPOD," a portable, phone-sized analyzer that takes just minutes to measure proteins in saliva that can indicate a developing disease in the mouth or possibly elsewhere in the body. To perform a test, dentists would simply collect a small saliva sample, load it into the diagnostic cartridge, start the assay, and have the diagnostic test results available by the time the patient's dental cleaning is completed. This research was supported by the National Institute of Dental and Craniofacial Research (NIDCR), part of the National Institutes of Health.

"The IMPOD is designed to measure up to 20 analytes, or biochemicals, at once," said Dr. Anup Singh, a chemical engineer at the Sandia National Laboratories in Livermore, Cal. and senior author on the paper. "We haven't scaled up to that point, but we are doing multi-analyte analyses in the laboratory. Our greatest need right now is validated biomarkers to enable further clinical studies. The basic engineering of the device has been completed."

The second development in salivary diagnostics is designed to help researchers like Dr. Singh find new and useful biomarkers in saliva. It is the creation of the Salivaoimics Knowledge Base (SKB). This knowledge base incorporates two diagnostics alphabets in saliva. One is a proteome alphabet. The other is a transcriptome alphabet. Each are mapped to 23 human chromosomes, totaling 1,166 distinct proteins and 851 unique mRNA transcripts in saliva. The information available in SKB includes profiles from healthy males and females, as well as oral cancer patients. The profiles will be used to determine distinct differences between groups of interest. The SKB will soon expand to include information for pancreatic cancer, breast cancer, lung cancer, ovarian cancer, diabetes, and Alzheimer's disease.

Dark Daily observes that these recent advances in salivary diagnostics are not likely to be familiar to most laboratory directors and pathologists. However, the potential of saliva-based testing to become popular with patients is obvious. Any diagnostic technology that can deliver a highly accurate test result without the need for the patient to be stuck with a needle is going to have appeal. As a collection method, many patients are already familiar with saliva, as saliva specimens are used for HIV screening and also for collecting DNA for paternity testing and other non-medical uses.

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