BOSTON, March 16 (UPI) -- Testing urine, saliva and other bodily fluids for
certain genetic mutations may prove a simple and non-invasive way to detect
head, neck, lung and other cancers. A study published in Friday's issue of
Science magazine found that the 20 bodily fluids tested had a 100 percent
sensitivity to the 60 tumors that were examined. While broad clinical studies in
patients with each type of tumor still are needed, David Sidransky, lead author
of the study, predicted that in a few years, cancer tests using bodily fluids
could be part of early cancer screening during routine physical exams.
"We still need better technology to process the test results, and we need to test larger
populations, but I think that if these tests are cheap enough, say less than
$200, people at risk will want them," Sidransky told United Press International.
Sidransky also is professor of otolaryngology and oncology at Johns Hopkins
University School of Medicine in Baltimore. He added, "I certainly think these
tests will be in common practice within two to three years for early diagnosis
of cancer, and eventually be available over the Internet." But for that to
become a reality, new technologies need to be available to reduce to about two
hours the 10 days it now takes to examine the fluid samples. Sidransky said some
of those technologies will come out of the Human Genome Project. "This research
is certainly quite remarkable if it is true. The tests will be extremely
valuable for clinicians," said Xin Wang, an investigator at the laboratory of
human carcinogenesis at the National Cancer Institute in Bethesda, Md. Current
cancer tests include X-rays, mammograms, colonoscopy and spiral CT scans.
The
bodily fluids are tested for mutations of the DNA in mitochondria, the small
organs that capture energy for use by cells. To date, bodily fluid tests for
cancer have centered on DNA in the nucleus of genes. But mitochondrial DNA is
about 1,000 times more prevalent than nuclear DNA, so mutations linked to cancer
are much easier to detect, Sidransky said. "This is a neat and new approach,"
said Dr. Bert Vogelstein, professor of oncology at Johns Hopkins University
School of Medicine. "We have known that the mitochondria in cancer cells appears
to be higher than in normal cells, but we did not know we could use that
information and the information in the mitochondria as ways to detect tumors in
fluids like saliva." He added, "There is a great need for non-invasive tests.
There is enough data in this study to warrant extensive clinical trials."
Vogelstein agreed with Sidransky that the tests could be available in a few
years. Vogelstein said it still is not clear how early in the formation of a
tumor the mitochondria unloads its DNA into bodily fluids. Bodily fluids could
be important in testing for breast and colon cancer. "Breast and colon cancer
are extremely hard to detect with non-invasive techniques now," Vogelstein said.
"The beauty of diagnostic assays to detect early neoplasia is that they are
non-invasive, and we may be able to treat the patient without surgery."
