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San Diego Union-Tribune,
January 6, 2007
By Bruce Lieberman
For biologist Ruth Gjerset, curing lung
cancer may require concealing a weapon in a kind of
Trojan horse.
The researcher, who works at the Sidney
Kimmel Cancer Center in La Jolla, is working on ways
to hide cancer-fighting genes inside stem cells grown
from a patient's bone marrow. Once injected into the
patient, the stem cells would theoretically carry the
anti-cancer genes to the appropriate sites.
Scientists haven't learned how to consistently
use such gene therapy without causing an immune reaction
that rejects the treatment and threatens the life of
the patient.
Gjerset believes stem cells are part of
the answer, and her idea has caught the attention of
a lung cancer foundation in New York City. Joan's Legacy,
named for an NBC News writer who died of lung cancer
in 2000, recently awarded Gjerset $100,000 to advance
her studies.
“We're real excited about the research
that Ruth is doing . . . and think that is the kind
of approach that's going to actually save lives,”
said Susan Mantel, the foundation's executive director.
Despite setbacks in early experiments
with gene therapy, many scientists say changing the
genes inside cancer cells would be a far more sophisticated
and effective way to battle cancer than the current
treatment: bombarding the body with chemotherapy and
radiation.
Lung cancer is a good target for new developments.
More people die from the disease than
any other type of cancer, said the national Centers
for Disease Control and Prevention in Atlanta.
In 2004, nearly 174,000 people in the
United States were diagnosed with lung cancer and more
than 160,000 died from the disease, the American Lung
Association estimated.
Smoking causes about 87 percent of lung
cancer cases, according to the association. Joan's Legacy
has worked to raise awareness of lung cancers not caused
by smoking.
Radon, a naturally occurring gas that
comes from rocks and dirt and sometimes can be found
in people's homes, raises a person's risk of getting
lung cancer. Exposure to asbestos, arsenic, chromium
and some forms of silica also increases the risk.
Alcohol abuse may play a role, too, although
it's difficult to say whether drinking or smoking is
the culprit because many people who drink also smoke.
Anti-smoking campaigns nationwide have
been so effective that many people wrongly believe that
if they don't smoke, they won't get lung cancer, Mantel
said.
But many people who have never smoked,
or who quit years ago, still get the disease. Physicians
need to find ways to diagnose the condition earlier
and treat it more effectively, she said.
“In a way, a lung cancer patient
is a victim of the success of the prevention forces
. . . (that) left research into effective diagnosis
and treatment virtually untapped,” Mantel said.
Gjerset said she had personal motivation
for wanting to combat lung cancer.
“I have friends who have had lung cancer, and
I have a friend right now who has lung cancer,”
said Gjerset, who lives in University City. “I
would very much like to be able to use my knowledge
to do something for these people.”
Gjerset, a graduate of the University
of California San Diego, with a major in biology and
a minor in music, completed her postdoctoral studies
at UC San Francisco's medical school. She then worked
as a researcher at the Pasteur Institute in Paris before
joining the Sidney Kimmel Cancer Center 14 years ago.
The gene therapy technique Gjerset hopes
to develop for lung cancer would be a multistep process.
First, she would engineer viruses to carry
the anti-cancer genes. Then she would hide those viruses
inside mesenchymal stem cells, which are grown from
a sample of a patient's bone marrow. Such stem cells
would not be rejected as foreign objects by the immune
system when they're injected back into the patient.
Once inside the patient's bloodstream,
the stem cells would migrate to cancerous tumors and
release the viruses. The viruses would then infect the
cancer cells, deliver their anti-cancer genes and halt
the tumors' growth.
“I'm hoping that within a two-to three-year period,
we'll know pretty well whether this approach is going
to be effective and can be actually used in patients
with cancer,” Gjerset said.
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