Though cancer in humans is not contagious, research is being influence by an ancient strain of transmittable cancer found in certain dogs. This sexually transmitted cancer causes genital warts and is shared from one dog to another. The significance of this long-lasting, spreadable cancer is the ability to study it and learn how it behaves to prevent future outbreaks.
In 2006, scientists discovered a rare genome in a certain type of dog that had been transferred from among dogs. Huskies and dogs of similar size and features are said to be at risk. Scientists were able date the cancer over 11,000 years back. The unique strain lives on with the same characteristics as the original disease. Dogs living is close quarters or in isolated areas were more likely to have the cancer. The genome shows that the dogs were inbred, which is likely how the cancer spread. Their immune systems were too similar to fight off the cancerous cells.
Recent studies are being led by Elizabeth Murchison, a researcher at the Department of Veterinary Medicine. Her and her team at the University of Cambridge are working on a Canine Transmissible Venereal Tumor (CTVT) study, as published in Science earlier this week. They are using more advanced technology to explore what the 2006 study found. They started by testing an infected Cocker Spaniel and Aboriginal camp dog. They found that their ancestry included Alaskan malamutes.
The major difference they found between the human and dog cancers were the number of cell mutations. While human tumors have thousands of mutations, the canine strain shows two million mutations that have occurred over the years. Murchison described the cancer as a parasite. The CTVT study shows that the dog cancer is treatable with chemotherapy because it doesn’t have the ability to adapt and survive. This is good news for Huskies and others similar dogs who have cancer or are at risk of getting it. Human tumors, on the other hand, are adaptable and have various different cells, which makes them difficult to treat.
It’s rare for a cancer cell to affect a different host. The only other transmittable cancer strain occurs through biting with Tasmanian devils. The Devil Facial Tumor Disease (DFTD) causes the devils to die within several months of being bitten. Unlike the cancer stain found in dogs, this cancer is untreatable. The research being done of dogs can help shed light on the devils too and give scientists the tool they need to prevent their untimely deaths.
Future cancer research on humans will be influenced by the contagious strain in dogs as well. Though there are no known occurrences of cancer spreading from one person to another, studying the history of the mutated cancer cells in dogs can help ensure that it won’t happen, or that there is at least a treatment plan in place to prevent it from becoming an epidemic. Early detection is the key since animals could spread diseases to people as well. In the meanwhile, Murchison and her team are trying to find out where the first canine cancer originated.
By Tracy Rose