‘Treasure in saliva’ may reveal deadly diseases early enough to treat them
Xinshu (Grace) Xiao and David Wong in Dr. Wong’s laboratory
October 28, 2014
UCLA research could lead to a simple saliva test capable of diagnosing—at an early stage—diabetes and cancer, and perhaps neurological disorders and autoimmune diseases.
The study, the most comprehensive analysis ever conducted of RNA molecules in human saliva, reveals that saliva contains many of the same disease-revealing molecules that are contained in blood. It was published online today by the peer-reviewed journal Clinical Chemistry and will be published in the journal’s January 2015 special print issue, “Molecular Diagnostics: A Revolution in Progress.”
“If we can define the boundaries of molecular targets in saliva, then we can ask what the constituents in saliva are that can mark someone who has pre-diabetes or the early stages of oral cancer or pancreatic cancer—and we can utilize this knowledge for personalized medicine,” said Dr. David Wong, a senior author of the research and UCLA’s Felix and Mildred Yip Endowed Professor in Dentistry.
Wong said the test also holds promise for diagnosing Type 2 diabetes, gastric cancer and other diseases. “If you don’t look in saliva, you may miss important indicators of disease,” Wong said. “There seems to be treasure in saliva, which will surprise people.”
RNA, widely known as a cellular messenger that makes proteins and carries out DNA’s instructions to other parts of the cell, is now understood to perform sophisticated chemical reactions and is believed to perform an extraordinary number of other functions, at least some of which are unknown.Wong’s research over the past decade has focused on identifying biomarkers in saliva.
His laboratory discovered that some of the same RNA that is inside human cells are also present in saliva and can be used to detect diseases—a surprising finding, he said, because enzymes in saliva can degrade RNA, making the mouth “a hostile environment.”</p> <p>The new research is a collaboration with Xinshu (Grace) Xiao, the paper’s other senior author and a UCLA associate professor of integrative biology and physiology. Using state-of-the-science genomics and bioinformatics, the researchers analyzed 165 million genetic sequences.
Among the many forms of RNA are some unusual ones that live in the mouth and in cells.
For example, it wasn’t known until very recently that RNA comes in a circular form; the linear form has long been known. But the UCLA scientists identified more than 400 circular RNAs in human saliva—the first discovery of circular RNA in saliva or any body fluid—including 327 forms that were previously unknown.