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Focus: Canine Co-operation

How dogs and cats are helping to solve a medical mystery Add to ...

The waiting room may resemble a zoo at times, but the vast majority of the patients are cats and dogs, whose sheer numbers provide a vast research pool.

Consider the facts: Canada has roughly eight million dogs and cats. One in four dogs will develop cancer, as will one in eight cats.

As well, naturally occurring cancers in dogs (unlike the cancers induced in mice) are biologically and clinically similar to those in humans - such as non-Hodgkin's lymphoma, melanoma and soft-tissue sarcoma.

In addition to lethal prostate cancer shared by dogs and people, the type of breast cancer that affects dogs spreads to bones, just as it does in women. And the most frequent canine bone cancer, osteo- sarcoma, is the same one that strikes people such as Terry Fox and Ted Kennedy Jr. in their teens.

In fact, it was Stephen Withrow, an internationally acclaimed scientist and professor at the College of Veterinary Medicine and Biomedical Sciences at Colorado State University, who made an important breakthrough working with dogs afflicted with osteosarcoma. He and his team developed a revolutionary limb-sparing technique that has been widely adapted for use on humans, significantly increasing the likelihood that children diagnosed with osteosarcoma will be cured.

Canine cancers, Dr. Mutsaers adds, also mimic those of humans in another way - metastasis, the often life-threat- ening spread of cancer cells to distant sites throughout the body.

As well, canine tumours - like those in a dog's owner - are influenced by the same key factors: age, nutrition, sex, reproductive status and environmental exposure.

"They're eating the same food. They're breathing the same air," says Geoff Wood, an associate professor of pathobiology at the college. "They're not contained in a germ-free environment. They have exposure to everything that we're exposed to. Physiologically, they're more like a human than mice are."

And, as in human cancer, canine cancer patients are treated with surgery, radiation and chemotherapy.

Dr. Wood, who heads a cancer-research program that uses both mice and dogs, says a turning point came with the public release in 2004 of the canine genome, which gave researchers the genetic arsenal they needed to "understand cancer in dogs, the same way we understand cancer in humans."

For two years, he has been designing a dog gene chip that he plans to use to compare the DNA of normal and diseased animals to uncover specific "markers" - bits of genetic material associated with disease genes. He expects to learn which genetic clusters are bad or benign in various patients - a technique that he hopes will lead to a better understanding of how human cancers progress.

THE NEW CENTRE

Established in 2007 as part of the university's Institute for Comparative Cancer Investigation, (which promotes greater integration of research in basic cancer biology and veterinary medicine), the Animal Cancer Centre currently has a staff of six, but the $20-million expansion, largely financed by the OVC Pet Trust Fund, will allow it to grow greatly, with the addition of: a medical oncologist, surgical oncologist, radiation oncologist, internal medicine specialist, medical oncology resident, surgical oncology resident, radiation oncology resident, three interns, five technicians and an additional four veterinary students.

Currently the cancer ward has about 2,500 patient visits a year, more often from communities in Ontario, Quebec, upstate New York and the Maritimes than far-off Korea. When the new centre opens next year, Dr. Stone, the college dean, expects that the patient load will triple.

Even without the new quarters, the centre's profile is on the rise. It was recently invited to join a U.S. consortium of top veterinary-teaching hospitals put together by Chand Khanna, a graduate of the Western College of Veterinary Medicine in Saskatoon, who interned at Guelph and is now head of head of the Comparative Oncology Program at the U.S. National Cancer Institute in Maryland.

Dr. Khanna, who was born in Kenya and moved to Toronto at the age of 3, created the Comparative Oncology Trials Consortium to track canine cancer treatment specifically to help develop drugs destined for human use.

Dr. Mutsaers calls it "a wonderful collaborative effort."

"We can enroll 100 bone cancer dogs at a time, or 50 with melanoma," he explains.

"These numbers, and the biological nature of the questions that can be answered, has led regulatory agencies like the Food and Drug Administration, and large and small pharmaceutical companies, to start to consider what questions our research might answer."

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