The world’s oldest cancer in dogs #cancer #dog

There is a most unusual cancer that occurs only in dogs. Not only is it contagious, it is also the oldest cancer in the world. By oldest, I don’t mean we’ve known about it the longest. When a dog has this form of cancer, the tumor cells themselves are 11,000 years old! The reason for that may lie in canine transmissible venereal tumor CTVT’s unique ability to infect dogs without ultimately causing much harm to them. Because they do not kill their hosts, the tumor cells stand a better chance of being passed on. The cancer cell lineage’s longevity and ability to pass between hosts has caused some scientists to consider it something like an independent organism — a transmissible parasite. There’s also evidence that the cancer cells might represent a group of dogs that has since disappeared. CTVT likely came from a dog in North America thousands of years ago. Today, those cancerous cells represent the only lasting descendants of the original dogs of North America.