Saliva Yields Clues to Detecting Oral Cancer
August 26, 2008
By: Laurie Edwards for Denta1
A recent study funded by the U.S. National Institute of Dental and Craniofacial Research discovered that saliva can be used to detect oral cancer in patients. The study is the first of its kind to demonstrate that patterns of messenger RNA linked to cancer found in saliva can designate the presence of developing tumors.
The findings, which appear in the current issue of Clinical Cancer Research, reported that scientists had a 91 percent accuracy rate in distinguishing between the saliva in healthy people and that of people diagnosed with oral squamous cell carcinoma – cancer of the mouth, neck, larynx and pharynx.
| Early signs that may indicate a need to screen for oral cancer: | Any lump or sore in the mouth that fails to heal and/or bleeds easily
A white or red patch in the mouth that will not go away
Thickening or soreness in the mouth, throat or tongue
Thickening or soreness in the mouth, throat or tongue |
The study used blood and saliva from 32 cancer patients who had not begun treatment. Analyzing the saliva, scientists isolated four distinct cancer-related molecules in mRNA, the substance that provides the chemical record that certain genes have been expressed. Since this method of diagnosis is quite new, the researchers matched all of their mRNA data with blood to make sure it was referenced correctly with the information in the blood.
To further validate their findings, the researchers re-screened the saliva without knowing whether the sample was extracted from a healthy person or cancer patient to see if they could tell just by the patterns of mRNA whether or not the person was sick. In nine-out-of-10 cases, they were correct in their assertions.
According to UCLA professor and the study’s senior author David Wong, D.M.D., D.M.Sc., the study proves saliva can potentially serve as a diagnostic tool but that it is by no means a cancer test at this point.
“This paper explores the translational utility of using saliva for cancer diagnosis. The work is good, but not good enough. Although we were able to identify the head and neck cancer patients with 91 percent sensitivity and accuracy, we missed one out of ten. With a larger study, we will move that specificity and accuracy closer to 100 percent,” he said.
The test has wide-ranging effects for other types of cancer as well. “Saliva is a mirror of our blood. We’re now conducting our initial studies of saliva as a possible diagnostic fluid for other human cancers and system diseases, and we should have our preliminary data in the spring,” said Wong.
Since mRNA is so plentiful in saliva and bodily fluid and processed much faster than other diagnostic resources, the fact that scientists have been able to isolate particular patterns that signal tumor growth is so significant.
“What really interested us was the idea that mRNA analyses could be performed in a bodily fluid as easily obtained as saliva. If correct, a salivary test in theory would be quick, painless and most likely less expensive than current diagnostic tests,” said Maie St. John, M.D., Ph.D., whose initial inquiries into mRNA and saliva helped spawn the eventual study.
Wong and his colleagues at UCLA plan on a larger, 200-person study to further validate the findings. The study’s aim is to pinpoint various stages of oral cancer and narrow in on an even more precise rate of accuracy.
Last updated: 26-Aug-08
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