| Newswise
— In one of the first studies using the RNA in saliva
to detect cancer, researchers at UCLA’s Jonsson Cancer
Center were able to differentiate head and neck cancer
patients from a group of healthy subjects based on biomarkers
found in their spittle. The study provides a first proof
of principle that may result in new diagnostic and early
detection tools and will lead to further studies using
saliva to detect other cancers.
Published in the Dec. 15, 2004,
issue of the peer-reviewed journal Clinical Cancer
Research, the study used four RNA biomarkers to detect
the presence of head and neck cancer with 91 percent
sensitivity and accuracy, said Dr. David Wong, professor
and chairman of Oral Biology and Medicine, director
of the UCLA School of Dentistry, Dental Research Institute,
and a Jonsson Cancer Center researcher.
“This is a new direction, using
a non-invasive fluid for disease diagnostics, particularly
in cancer,” said Wong. “This is our proof of principle.
We now hope to demonstrate the utility of saliva for
systemic diagnosis of other diseases such as breast
cancer.”
Typically, cancer researchers
use blood serum and urine to look for cancer signatures.
Saliva contains the same biomarkers for disease that
are found in the blood, but they are present at much
lower levels of magnitude. The emergence of nanotechnology
allowing scientists to manipulate materials on an
atomic or molecular scale helped researchers uncover
the components of saliva, Wong said, and “changed
the whole scene” for UCLA scientists.
“It gave us the clue to look
at what else is in saliva,” Wong said.
Of the 3,000 RNA biomarkers
found in saliva, Wong and his team discovered that
a combination of four provided a detectable signature
for head and neck cancer. That signature was identified
in cancer patients with 91 percent accuracy.
“This paper explores the translational
utility of using saliva for cancer diagnosis,” Wong
said. “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.”
In the study, Wong and his
colleagues enrolled 32 subjects with head and neck
cancers - cancers of the mouth, tongue, larynx and
pharynx. They also enrolled 32 age and gender matched
subjects without cancer but with the same smoking
history to act as a control group. Using their saliva,
researchers were able to discriminate the cancer patients
from the control group, Wong said.
“We tested the hypothesis that
distinct RNA expression patterns can be identified
in cancer patients, and the differentially expressed
transcripts can serve as biomarkers for cancer detection,”
the study states. “Moreover, using saliva as a diagnostic
fluid meets the demands for inexpensive, non-invasive
and accessible diagnostic methodology.”
Dr. Judith C. Gasson, director
of the Jonsson Cancer Center and a professor of biological
chemistry and medicine, called Wong’s work exciting.
“This is a perfect example
of the type of groundbreaking research the Jonsson
Cancer Center encourages and supports,” Gasson said.
Wong and other researchers
next will attempt to validate the study’s findings
in a much larger study of about 200 oral cancer patients
conducted at UCLA’s Jonsson Cancer Center and at four
other national centers. The study is now recruiting
early and late stage head and neck cancer patients
to participate. Study volunteers will need to provide
saliva and blood serum to participate. To take part
in the UCLA study, volunteers can call 1-888-798-0719.
More than 1.3 million new cases
of cancer will be diagnosed in the United States this
year alone, resulting in more than 563,000 deaths
– one person every minute. The goal of any cancer
screening program is to detect tumors at an early
stage, when they are most treatable. And the best
new screening tools should be inexpensive and non-invasive,
so they’ll be widely used. The results of Wong’s study
will open new research directions that may prove saliva
is a suitable tool for the development of non-invasive
diagnostic, prognostic and follow-up tests for cancer.
The study was funded by the
Jonsson Cancer Center and the National Institute of
Dental and Craniofacial Research
UCLA's Jonsson Comprehensive
Cancer Center is made up of more than 240 cancer researchers
and clinicians engaged in cancer research, prevention,
detection, control, treatment and education. One of
the nation's largest comprehensive cancer centers,
the Jonsson Cancer Center is dedicated to promoting
cancer research and applying the results to clinical
situations. In 2004, the Jonsson Cancer Center was
named the best cancer center in the western United
States by U.S. News & World Report, a ranking
it has held for five consecutive years.
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