at Forefront in Fight Against Cancer
Veterinary oncologists are
hard to come by. Training programs, which can take as long as seven
years post-DVM, are few and far between. Once an oncologist is ready
to join the work force, the lure of high salaries and urban locations
in the private sector make it difficult to secure faculty oncologists.
Illinois is lucky indeed
to have an oncological "dynamic duo" with the partnership between medical
oncologist Barbara Kitchell and surgical oncologist Nicole Ehrhart.
The two combine their clinical practice and teaching with research that
is attacking cancer on several fronts and making advances for both human
and animal medicine. Their efforts and success in the research sector
make the College's Veterinary Cancer Care Clinic rank among the veterinary
elite, according to Dr. Kitchell.
The College's cancer program
draws on a broad arsenal that includes traditional surgery, chemotherapy,
and radiation as well as new approaches such as cytostatic therapy,
immunotherapy, and gene-based diagnostics.
most of the clinicians, diagnosticians, technicians, and researchers
on the oncology team: front, from left, Dr. Cathy Greenfield, Dr. Nicole
Ehrhart, Nancy George, Dr. Joanne Messick, Kismet the dog, Jennifer
Rose; back, from left, Dr. Joseph Impellizari, Dr. Curt Daly, Dr. Monika
Haefner, Dr. Timothy Fan, Shari Poruba, Dr. Barbara Kitchell, Dr. Louis-Phillipe
deLorimier, Dr. Pamela Jones, Dr. Matt Wallig, Heather Soder, Dr. Sara
Ayres, Char Werts, Dr. David Lurie, and Dr. John Hintermeister.
Cytostatic Therapy Holds
"In the clinic,
we are a chemotherapy trial center and we are a translational modeling
center," says Dr. Kitchell. The purpose of a translational modeling
center is to prove principles of therapeutic concepts developed in the
research laboratory and pass them on as models to the human medical
For example, current research
in dogs is testing a compound known as a metastasis blocking agent to
see if it can inhibit the effect of matrix metalloproteinases, enzymes
that eat the tissue between cells thus allowing the cells to break apart
and scatter throughout the body. Cancerous cells can spread throughout
the body because of these enzymes. If the metastasis blocking agent
works, the spread of cancer can be stopped. The success of this research
could significantly contribute to veterinary and human health.
"If this works, we could
be looking at a significant advance in cancer therapy," says Dr. Kitchell.
Blocking the enzymes known
to spread cancer is an example of cytostatic therapy. Traditional cancer
treatment is cytotoxic, killing cancer cells but causing side effects
in the patients. The use of cytostatic therapy could turn cancer from
a chronic fatal disease to a chronic manageable disease, like diabetes
The College is a leader
in this project, with veterinary research trials ahead of human trials
of a similar compound. The advantage of conducting trials first with
animal patients is that enzymes such as matrix metalloproteinases also
serve normal functions in the body, and the negative effects of blocking
them are relatively unknown. And since cancer is the leading cause of
death among dogs and cats, Dr. Kitchell and her team of researchers
can study the naturally occurring disease in patients whose owners agree
to the trial, rather than inducing the disease in healthy animals.
Genes, and More
On the immunotherapy
front, Dr. Kitchell's team is examining anti-cancer vaccine strategies
that would recruit the immune system to identify and kill cancer cells
or clean up the cancer cells left after chemotherapy, radiation, and
In the research lab, the
team is working on several molecular biology projects, one of which
has involved cloning genes for matrix metalloproteinases from the dog.
Cloning the genes makes the recombinant protein, which in turn allows
one to create antibodies against the protein. This work could ultimately
lead to early-detection diagnositic kits as well as improved treatment
for specific cancers.
Another project involves
studying the impact of compounds that might inhibit cancer cell immortalization.
Normal body cells have a finite number of divisions in their lifetime.
For example, after skin cells age and become senescent, the skin begins
to wrinkle and heals more slowly. Cancer cells, on the other hand, can
continue to divide well beyond the normal cell life expectancy, growing
within the body and spreading the cancer. Dr. Kitchell's research team
is evaluating compounds that could stop immortalization of cancer cells.
Anti-cancer drugs are also
being studied. Dr. Kitchell is experimenting with time-released chemotherapy
delivery systems that deliver drugs directly into a tumor. She is also
examining markers of resistance to anti-cancer drugs so that she can
predict which drugs will be best for patients.
Bone Transport Studies
Last spring, Dr.
Nicole Ehrhart found that a new process called bone transport could
spare the limbs of dogs with bone cancer. The technique of growing new
bone with the help of a special ring fixture, known as an Ilizarov,
was thought to hold potential benefit for humans--especially children--with
bone cancer as well. Human bone had been regenerated in patients who
had been the victims of accidents, but it was unclear how chemotherapy
would affect the bone growth.
According to Dr. Ehrhart,
continued study proves that chemotherapy can be given to patients without
harming the new bone. Therefore, human cancer patients receiving chemotherapy
are viable candidates for this new bone-sparing device.
Now this study of the effects
of chemotherapy on bone growth has raised a new initiative for the veterinary
oncology team. Though chemotherapy may not harm bone growth, radiation
has been found to be an inhibitor. Dr. Ehrhart's latest challenge is
to find out how to overcome the negative effects of radiation.
Radiation shuts down normal
tissue processes while it stops the growth of a tumor. Dr. Ehrhart would
like to discover how to "turn back on" the normal tissue growth. Currently
she is studying bone morphogenic proteins--growth factors that encourage
the growth of bone--to see whether they might be helpful in facilitating
normal tissue processes.
Dr. Ehrhart is also working
with pediatric oncology scientists from the University of Arkansas Medical
School to discover how the signaling pathways of stem cells are changed.
As Dr. Ehrhart explains, "Stem cells circulate throughout the body to
help regenerate damaged tissue. During radiation treatments, stem cells
are not killed, but they are not able to receive signals to enable them
to turn into their respective tissue." Discovering how these signaling
pathways are changed may lead to answers on why radiation inhibits bone
and Surgery: A One-Two-Three Punch
In another instance
of human and veterinary medicine working hand in hand, Dr. Kitchell
and Dr. Ehrhart are investigating how chemotherapy treatment before
bone surgery could give dogs a better chance at surviving bone cancer.
Human medicine studies have
already shown that in patients with bone cancer, those who receive chemotherapy
before surgery, as opposed to after surgery, could have a survival advantage.
This evidence came to light quite accidentally, as doctors needed to
treat the cancer of patients who had to postpone surgery until their
prostheses could be custom-made.
"Traditionally with bone
cancer, we've done surgery and then chemotherapy," says Dr. Ehrhart,
who throughout the next year will be treating canine patients requiring
surgery with chemotherapy both before and after their surgical procedure.
Nutrition Support for
are not the only focus of Ehrhart's studies. She knows that cats suffering
from cancer lose a significant amount of weight during the course of
their illness. She would like to find out what happens to body tissues,
including fat, muscle, and bone, during cancer treatment. It is unclear
whether the weight loss stems from loss of fat or muscle. It is also
unclear whether the loss of tissue can be attributed to the cancer itself
or to the diet of the cat.
The study will require 100
cats per year for at least two years. Owners will receive some compensation
for allowing their cats to participate in the study.
According to Dr. Ehrhart,
her goal is to see "what we can do to improve cats' quality of life
as well as quantity of life. We want to give them optimal nutritional
Working Together for
may vary in scope and size, affecting animals and humans, large and
small, but the ultimate goal of finding a cure for cancer underlies
"Cancer is one of the medical
battlefields of modern life. The thought that motivates me the most
is the knowledge that, one day, a child will not have to have an amputation
because of our work," says Dr. Ehrhart. "The idea that we have contributed
to human cancer research and yet hundreds of dogs and cats with cancer
will also benefit, is evidence that physicians and veterinarians are
truly practicing one medicine. We are all fighting the same battle."
From left: Drs.
Gordon Baker, Barbara Kitchell, and Pamela Jones, of the College of
Veterinary Medicine, accept a check for $50,000 from Dr. Michele Habrecht,
Purina's technical support manager.
Funds Veterinary Oncology Residency
Ralston Purina is
contributing to new learning about how nutrition can help dogs and cats
with cancer by funding a comparative oncology medicine residency at
the University of Illinois College of Veterinary Medicine.
Purina recently renewed
its commitment to continue funding the oncology residency by providing
$50,000 during two years. Pam Jones, a 1998 graduate of Colorado State
University College of Veterinary Medicine and Biomedical Sciences, will
continue in her second year as the Purina comparative oncology medicine
resident. Dr. Jones will study the effect of specific nutrients in helping
animals maintain normal tissue while undergoing radiation therapy.
"The University of Illinois
oncology residency allows Purina to be involved with research aimed
at advancing the role of nutrition in the field of cancer medicine,
says Dr. Aine McCarthy, Purina's director of veterinary professional
communications. "It also helps to increase awareness of the importance
of nutrition in veterinary care overall and presents an opportunity
to share the science that goes into learning more about nutrition for
Funding for the oncology
residency comes from the Purina College Program, which conducts educational
outreach activities at all U.S. veterinary schools and veterinary residencies
at Tufts, Minnesota, and UC-Davis as well as at Illinois. Ralston Purina,
the world's largest producer of dry dog and dry and soft-moist cat foods,
also produces a veterinary dietary line for dogs and cats with special