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Senior Citizen Health & Medicine
Urine Test Leads to More Accurate Diagnoses of
Prostate Cancer
Far more accurate than the PSA blood test currently
in use worldwide
 Feb. 1, 2008 A simple urine test that screens for
the presence of four different RNA molecules accurately identified 80
percent of patients in a study who were later found to have prostate
cancer, and was 61 percent effective in ruling out disease in other
study participants, according to researchers at the University of
Michigan. This test is more accurate than other available screening
methods, they say.
This is far more accurate than the PSA blood test
currently in use worldwide, which can accurately detect prostate cancer
in men with the disease but which also identifies many men with enlarged
prostate glands who do not develop cancer, researchers say. Even the
newer PCA3 test, which screens for a molecule specific to prostate
cancer and which is now in use both in the U.S. and Europe is less
precise, they say.
"Relative to what is out there, this is the best
test so far," said the study's lead author, Arul Chinnaiyan, M.D.,
Ph.D., director of the Michigan Center for Translational Pathology at
the University of Michigan.
He also says that this "first generation multiplex"
biomarker test will likely be improved upon as researchers continue to
uncover the molecular underpinnings of prostate cancer.
"We want to develop a test to allow physicians to
predict whether their patients have prostate cancer that is so accurate
a biopsy won't be needed to rule cancer out," Chinnaiyan said. "No test
can do that now."
The study is published in the February 1 issue of
Cancer Research, a journal of the American Association for Cancer
Research.
Chinnaiyan and the Michigan researchers developed
the test based on their recent finding that gene fusions - pieces of
chromosomes that trade places with each other, causing two genes to
stick together - are common in prostate cancer, and that by overriding
molecular switches that turn off excess growth, they may be the
causative factor in some forms of the disease. In 2005 they identified a
prostate-specific gene called TMPRSS2 which fuses with either ERG or
ETV1, two genes known to be involved in several types of cancer. In
2007, they identified another five genes that fuse on to ERG or ETV1 to
cause prostate cancer.
In the current study, researchers built upon the
PCA3 test by screening for six additional biomarkers, including
TMPRSS2:ERG as well as some molecules generally over-expressed in
prostate cancer, and some which are over-expressed in specific cancer
subtypes.
Researchers collected urine samples from 234 men
with rising PSA levels before they underwent prostate biopsy at a
University of Michigan urology clinic. Among this group, biopsy results
confirmed a diagnosis of prostate cancer in 138 patients; 96 patients
were cancer-free.
Correlating the urine biomarker test results with
the biopsy data, researchers found that, in combination, four of the
seven biomarkers were significant predictors of prostate cancer: GOLPH2,
which is generally over-expressed in prostate cancer; SPINK1,
over-expressed in a subset of these cancers; the PCA3 transcript
expression; and TMPRSS2:ERG fusion status. Of the seven markers, only
PCA3 had been previously reported as a diagnostic biomarker.
When tested as individual biomarkers, GOLPH2, PCA3,
and SPINK1 each outperformed PSA, which had identified all of the men in
the study as potentially positive for prostate cancer. "PSA was not
predictive at all," Chinnaiyan said. "You might as well have flipped a
coin."
The combination of the four biomarkers achieved a
specificity and positive predictive value of greater than 75 percent,
which they found to be five percent better than use of a PCA3 test
alone, he says. Specificity is the probability that a test indicates a
negative result if a person does not have a disease, and the positive
predictive value is the proportion of patients with positive test
results who are correctly diagnosed.
Chinnaiyan believes that any tests that are
developed and widely tested would first be used to supplement a PSA
blood screen.
The study was funded by the Early Detection
Research Network, Department of Defense, the National Institutes of
Health, the Prostate Cancer Foundation, and Gen-Probe Incorporated of
San Diego. The gene fusion technology has been patented by the
University of Michigan and licensed to Gen-Probe Inc, which is also
developing the PCA3 screening test. Chinnaiyan is a paid consultant to
Gen-Probe.
Editors Notes:
The mission of the American Association for Cancer
Research is to prevent and cure cancer. Founded in 1907, AACR is the
world's oldest and largest professional organization dedicated to
advancing cancer research. The membership includes nearly 27,000 basic,
translational, and clinical researchers; health care professionals; and
cancer survivors and advocates in the United States and more than 70
other countries.
American Association for Cancer Research
Links to more SeniorJournal.com reports on
Prostate Cancer:
New Male Sling Helps Prostate Cancer Survivors with
Urinary Incontinence
Losing urine control is frustrating for the
more than 2 million men -
Aug. 29, 2007
Cancer Cells Zapped by Electrical Impulses with Invention by Engineers
Clinical trials come next for test on prostate cancer victims
July 6, 2007
Researchers Say They
Have Found a Better Test for Prostate Cancer?
April 26, 2007
Proteins from Inflammation are 'Smoking Gun' in Spread of Prostate
Cancer
March 19, 2007
Obesity and
Prostate Cancer a Deadly Combination, Study Finds
March 15, 2007
Seniors May Increase Risk of Heart Disease from Prostate Cancer
Treatment
Feb. 26, 2007
Prostate Cancer
Patients Have High Survival Rates with Seed Implants
January 31, 2007
Radiation Therapy
Combo Cures Prostate Cancer Long-Term
January 4, 2007
Lack
of Sons Puts Men at Higher Risk for Prostate Cancer Says New Study
January 3, 2007
Elderly Men
Survive Prostate Cancer 'Significantly' Longer if Treated
December 22, 2006
Octogenarians Not Too Old for Cancer Surgery, Say Mayo Clinic
Researchers
November 27, 2006
Prostate
Cancer Studies Find Benefit to Radiation, No Harm in Testosterone
Replacement in Older Men
November 14, 2006
Prostate
Cancer Cells Killed by Protein Made by the Cancer
November 10, 2006
Researchers
Urge New Approach to Prostate Cancer Screening with Early PSA Base
November 1, 2006
Prostate Cancer Appears Cured in 89 Percent of Men Treated with IMRT
September 27, 2006
PSA of
Prostate Cancer Victims Can Predict How Long They Will Survive
August 25, 2006
Large Study Finds Some Prostate Cancer Patients
Possibly Overtreated
August 15, 2006
Plant-Based Diet with Stress Reduction Slows
Progression of Prostate Cancer
August 15, 2006 - Also in this news report you will find links
to more associations between prostate cancer and nutrition and
supplements.
Prostate Cancer Cells Killed by RNA-Based Drug
August 10, 2006
Men Found with Prostate Cancer Rush to Judgment on
Treatment
June 26, 2006
Potential of Prostate Cancer Spread Detected Early
by New Test
June 21, 2006
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