The US news programme 60 Minutes has aired an episode on the key role research using dogs plays in the search for drugs and treatments for cancer, in both humans and animals.
CBS reporters spoke to scientists from the National Institutes of Health (NIH), who are using dogs, that already have cancer, in clinical trials.
As in humans, cancer is also very common in dogs, with estimates that one in four will develop the disease, amounting to 4 million dogs in the US alone each year.
In the programme (from 1m.46s), Elaine Ostrander, at NIH, explained that because some dog breeds are more predisposed to certain cancers, it is much simpler to study these groups of dogs than humans, where there are more complex factors.
Clinical trials in dogs can also pave the way for human trials. A study in pet dogs that successfully treated the bone cancer osteosarcoma, using modified bacteria, led to the US Food and Drug Administration approving a phase II clinical trial for children and teenagers last year.