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Conquest - Cutting Cancer Risks, Solving Cancer Mysteries
Making the Connection 2001-2008
Cutting Cancer Risks, Solving Cancer Mysteries
Date: April 20, 2010
CRF Making Healines in 2005
Investigators studied an enzyme called
GSTP1 that may protect prostate cancer
cells against environmental damage from
smoke and other chemicals. The enzyme
was found to play a key role in preventing
precancerous prostate lesions from turning
malignant. When functioning correctly,
the gene appears to detoxify
carcinogens. However, in people with
prostate cancer, the gene may have been
deactivated. Investigators are exploring the
possibility of therapeutically inducing
protective enzymes that would restore
and/or compensate for missing or low levels
of the enzyme GTSP1. ?
HELPING KICK THE HABIT
Free nicotine patches, funded by the
Maryland CRF, were distributed to smokers
in a joint study by Johns Hopkins and
the Washington County Health Department.
The patches increased the number
of participants in cessation programs and
helped 27 percent more people quit
smoking, at least for a period of time, says
Johns Hopkins CRF investigator
ANTHONY ALBERG, PH.D. , M . P. H .
Long-term quit rates were not affected.
Alberg says smokers will attempt to quit
several times, and nicotine replacement
therapies are an effective option. “No matter
how long smokers have smoked, when
they quit, it prolongs their lives.” ?
SIZE MATTERS: SHORTENED
CHROMOSOMES ARE A SIGN
OF EARLY CANCER
Just as the plastic protective coverings on
the end of shoelaces protect the laces,
telomeres, the end caps on chromosomes,
preserve genetic integrity. CRF researcher
ANGELO DEMARZO, M.D. , P H . D. ,
and Alan Meeker, M.D., Ph.D., have evidence
that they play a role in the early
development of many types of cancer.
The investigators studied tissue taken
from small precancerous lesions in the
bladder, esophagus, large intestine,
mouth and cervix and found shortened
telomeres 97 percent of the time. Telomeres
protect the interior, gene-containing
parts of the chromosome from being
accidentally lost. As normal cells divide
and age, some of the telomere DNA is
lost, and the telomeres get progressively
shorter. Normal cells monitor the length
of their telomeres and initiate cell death
if they get too short. If this monitoring
system breaks down, cancer can be initiated.
Assessing telomere length may provide
a new direction for cancer
prevention and early diagnosis studies,
says DeMarzo. ?
SOLVING THE MYSTERY
OF THE DISAPPEARING
CRF research shed light on why cervical
precancers disappear in some women and
not in others and helped pinpoint which
women would benefit from a cervical
cancer vaccine developed and studied at
the Kimmel Cancer Center. The strain of
HPV and the genetic characteristics of a
woman’s immune system seem to be the
key. The lifetime risk of becoming infected
with a high-risk strain of HPV, at least
once, is over 80 percent, so why do only
a small percentage of these infections
progress to full-blown cancers? In her study
of 100 women with high-grade precancerous
lesions, CONNIE TRIMBLE,
M.D. , is studying immunologic characteristics
that may help solve this mystery
and identify women whose immune system
may need help to get rid of the cervi-cal lesions. She found that the immune
systems of women infected with a specific
viral strain, called HPV16, had the most
trouble in clearing the cervical lesions.
“Among women with non-HPV16
lesions, those carrying an immune-system-
related gene called HLA*A201 were
three times less likely to have their
immune systems resolve their lesions.
Understanding the characteristics of these
lesions will help us determine women
who may best benefit from our vaccine,”
she says. “Some lesions are on the brink
of resolving, but may need the vaccine to
make it happen.” ?
MARYLAND’S POOR HAVE
INCREASED CANCER RISK
FROM AIR POLLUTION
Maryland communities that are poor and
predominantly African-American incur a
disproportionate cancer risk from
ambient exposure to airborne toxins,
according to Johns Hopkins researchers,
including CRF investigator TIMOTHY
BUCKLEY, PH.D. , M . H . S . Their
study revealed that among Maryland census
tracts, the poorer the community and
the higher the proportion of African-
Americans, the greater the residents’
cancer risk from air toxins. Further, the
researchers were able to identify the
sources underlying the inequities. Both
traffic and area sources (e.g., dry cleaners
and gas stations) were primarily responsible,
in contrast to point sources (e.g.,
power plants, heavy industry) and nonroad
mobile sources (e.g., construction,
farm vehicles and airplanes), which were
more evenly distributed across Maryland’s
economic and racial strata. The study is
published in the June 2005 issue of
Environmental Health Perspectives. ?
STATINS HELP CUT RISK OF
ADVANCED PROSTATE CANCER
In a 10-year study of more than 30,000
health professionals, researchers at Johns
Hopkins and Harvard found that the
longer men take cholesterol-lowering
drugs such as statins, the far less likely
they are to develop advanced prostate
“We found that statin-takers cut their
risk for advanced disease in half,” says
ELIZABETH PLATZ, SC.D. , M . P. H .
Although earlier, smaller studies have
linked the use of statins to a lower risk of
prostate and other cancers, such as breast
and colon, this was the first to tie risk
reduction to prostate cancer stage while
tracking the medication use before study
participants got cancer.
Still, the researchers caution that data
are not conclusive enough to warrant
prescribing the drug to reduce cancer risk
alone because many questions still linger,
such as how they might contribute to
delaying the cancer process more effectively
than non-statins. ?
EARLIER USE OF PROSTATE
CANCER VACCINES URGED
Timing is everything when it comes to
killing prostate cancer cells with specially
tailored vaccines, say scientists testing the
drugs in mice. “The window of opportunity
is narrow for vaccination, designed
to reinvigorate the immune system’s
attack on cancer cells, and it occurs right
after hormonal therapy begins to wipe
out the tumor and immune cells outnumber
cancerous ones,” according to
CRF Investigator CHARLES DRAKE,
M.D. , P H . D. , director of this research
published in Cancer Cell.
In the Hopkins studies with mice bred
to develop prostate cancer, Drake and his
collaborators at the University of Connecticut
found that the animal’s immune
system recognizes the cancer but fails to
mount an attack, probably because
immune cells become tolerant of the
slow-growing cancer. ?
SECONDHAND SMOKE LINKED
TO CERVICAL CANCER
Exposure to secondhand cigarette smoke
increases the risk of developing cervical
tumors, according to researchers at the
Johns Hopkins Bloomberg School of Public
Health and Kimmel Cancer Center.
The researchers’ results also corroborated
past studies that found an association
between active cigarette smoking
and cervical neoplasia — the growth of a
tumor. The concept of the Johns Hopkins
study was the result of collaboration among
several researchers supported by the
Maryland Cigarette Restitution Fund.
The study is published in the January
2005 issue of Obstetrics & Gynecology. ?
CRF INVESTIGATORS RECEIVING HONORS AND AWARDS
STEPHEN B. BAYLIN, M.D. , was awarded the 2005 Simon M. Shubitz Cancer Prize
and Lectureship awarded in honor of the late Simon Shubitz, a distinguished alumnus of the
University of Chicago, and given in recognition of excellence in cancer research.
KALA VISVANATHAN, M.B. B. S . , F. R . A . C . P. , M . H . S . , was one of 13 recipients
of the American Society of Clinical Oncology Young Investigator Career Development
Awards. Visvanathan received $170,000 as part of a three-year grant.
LEISHA EMENS, M.D. , P H . D. , received the AVON Clinical Trials Award for her
work on a breast cancer vaccine.
New CRF research sheds light on why
cervical precancers disappear in some women
and not in others and helps pinpoint which
women would benefit from a cervical cancer
vaccine under development and study at the
Kimmel Cancer Center.