Now new research proves that the same medicine used to treat our pets' deadly diseases may also save humans.
Two dogs, one cat, a couple of veterinarians and a neurosurgeon are all part of a team that may find new medicines for a very painful and deadly disease in people and pets.
"She had the most amazing, uncontrolled thirst," said Lynn Rainker, owner of a dog named Maggie.
Both people and pets with Cushing's disease develop tumors, diabetes, high blood pressure, weight gain, and weakened bones. Without treatment, it's fatal. But surgery to remove the pituitary tumor in animals is almost impossible.
But a team at Cedars-Sinai Medical Center modified an HD surgical imaging device they created for their patients to help veterinary surgeons see the tumor in animals.
Not only can surgeons remove the tumor saving the animals, but then researchers take the dog's tumor, create a model, compare it to the humans, and then test therapies that can benefit both.
"We have made some early discoveries that are already beginning to translate into potential clinical therapies for dogs, and hopefully down the line into people," said Dr. Adam Mamelak, neurosurgeon, Cedars-Sinai Medical Center.
Drugs that shrink the tumors are now being tested first in dogs and then possibly later in humans.
"We just know he's feeling so much better. He can rest. He's got a great appetite," said Dr. Mamelak.
Man's best friend may also be the best chance to understand human cancer. A one-of-its-kind program at the University of Pennsylvania School of Veterinary Medicine is matching sick shelter dogs with willing owners, and advancing knowledge of human breast cancer at the same time.
When Millie Edmonds adopted Cali, she had no idea the dog had 12 tumors in her mammary glands. But you could say the two were destined to be together. Millie is a two-time cancer survivor.
Cali gets free care as part of the Shelter Canine Mammary Tumor Program. Canine tissue samples are collected for scientists to compare with human ones.
Unlike humans, dogs have five pairs of mammary glands. Most dogs who have tumors in one gland will develop others.
"So if we can figure out what happens when a tumor becomes malignant, what are the most important genetic alterations, maybe there will be a target that can be drugged," said Dr. Karin Sorenmo, oncologist, University of Pennsylvania School of Veterinary Medicine.
Potentially stopping the spread of the cancer cells, Edmonds says Cali is part of the family -- a family with a history of cancer that she hopes will stop before her granddaughters come of age.
"If they didn't have to worry about it, that would be the best thing," said Edmonds.
All of the dogs used in the trial came from shelters. Only 10 percent of animals taken into shelters have been spayed or neutered. Dogs that are not spayed are at least four times more likely to get mammary tumors.