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Study finds
that Blood Test can gauge Prostate Cancer
risk
Newswise — New genomics
research has found that a simple blood test
can determine which men are likely to
develop prostate cancer.
Researchers at Wake
Forest University School of Medicine and
colleagues found that five genetic variants
previously associated with prostate cancer
risk have a strong cumulative effect.
Reporting in New
England Journal of Medicine, researchers
found that a man with four of the five
variants has an increased risk of 400 to 500
percent compared to men with none of the
variants.
The researchers then
added a family history of prostate cancer to
the equation – for a total of six risk
factors. A man with at least five of the six
factors had increased risk of more than 900
percent.
The article was
published “Online First” today and will be
included in the Feb. 28 print issue.
The scientists say each
variant was independently associated with
prostate cancer risk and that the variants
are fairly common in the population.
Together, these
five variants and a family history accounted
for almost half (46 percent) of prostate
cancer patients.
The study involved
analyzing DNA samples from 2,893 men with
prostate cancer and 1,781 healthy
individuals of similar ages – all
participants of a prostate cancer study in
Sweden.
“This is significant
and could affect clinical care,” said senior
researcher Jianfeng Xu, M.D., Dr. PH.,
professor of epidemiology and cancer
biology.
“The information could
substantially improve physicians’ ability to
assess risk and determine the need for more
aggressive screening or even a biopsy.”
For example, the test
may be especially useful in men with a
family history of prostate cancer or those
who have a marginally elevated PSA (prostate
specific antigen), he said.
The study is also
important because it is one of the first to
illustrate how a combination of several
genes can affect risk of disease.
Genomics teams
nationwide are currently searching for
combinations of genes that may underlie
common diseases such as cancer, diabetes and
asthma.
Currently, age, race
and family history are the three factors
associated with increased risk of prostate
cancer.
Family history is
believed to account for about 10 percent of
prostate cancer cases. Strikingly,
researchers estimated that the five variants
combined could account for about 40 percent
of cases.
“Our finding provides
an opportunity to supplement the
well-established risk factors by looking at
how many of these variants a man has
inherited,” said Xu. “It may provide a much
better weapon to guide clinicians.”
Until last year, no
specific genetic variants had been
consistently identified as markers for
prostate cancer risk.
Then, advances in
technology allowed researchers to take a
more systematic approach to looking at the
entire genome.
Instead of solely
studying genes that they suspected were
related to disease susceptibility, they
could study the entire genome and look for
associations.
Through these searches,
several research teams identified five
genetic locations associated with risk of
developing prostate cancer: three on
chromosome 8q24, one on chromosome 17q12 and
one on 17q24.3.
Each variant alone was
associated with moderate risk, but the
effect wasn’t considered significant enough
to justify testing individuals.
The current study was
the first to evaluate whether there is a
cumulative effect from having multiple
variants.
“When we considered the
variants together we discovered their
potential for predicting individual risk,”
said Xu.
Because of the
cumulative effects of these risk variants
and family history, for the first time
associations found through genome-wide
screening appear to be useful in clinical
practice.”
The researchers said
further study is needed to determine how
their findings of genetic testing may
complement PSA (prostate-specific antigen)
testing. The researchers found that the risk
associated with the genetic variants is
independent of PSA results.
“This suggests that a
subset of men deemed to have a low risk of
prostate cancer based on their PSA levels
may in fact be at significantly elevated
risk due to inheriting one or more of the
genetic variants,” said S. Lilly Zheng,
M.D., associate professor of internal
medicine and the first author of the paper.
Genetic testing of
these five variants will soon be offered at
a CLIA (Clinical Laboratory Improvement
Amendments)-certified laboratory at Wake
Forest University School of Medicine. For
more information, visit the website
http://www.ProactiveGenomics.com or call
866-487-2344.
Co-researchers include
senior author Henrik Gronberg, M.D., Ph.D.
professor at the Karolinska Institutet in
Stockholm, Sweden, and William B. Isaacs,
Ph.D, professor at Johns Hopkins Medical
Institutions in Baltimore, Md.
Wake Forest University
Baptist Medical Center is an academic health
system comprised of North Carolina Baptist
Hospital and Wake Forest University Health
Sciences, which operates the university’s
School of Medicine. U.S. News & World Report
ranks Wake Forest University School of
Medicine 18th in family medicine, 20th in
geriatrics, 25th in primary care and 41st in
research among the nation's medical schools.
It ranks 35th in research funding by the
National Institutes of Health. Almost 150
members of the medical school faculty are
listed in Best Doctors in America.
