Dogs may hold the key to further research and breakthroughs in cancer studies and trial treatments, according to recent comparative oncology research.
Four million dogs in the U.S. are diagnosed with cancer every year. Many of these cancers are the same kinds that humans can develop. Lymphoma, melanoma, brain cancer, breast cancer, and the deadly bone cancer osteosarcoma are some of the many cancers that dogs are diagnosed with, as well as humans.
Doctors and scientists are looking closely at what they use in clinical trials for canines to develop potential treatments for both humans and dogs. This method, comparative oncology, is funded partly by the Cancer Moonshot Initiative, launched in 2016. According to the initiative’s website, it has three goals: “to accelerate scientific discovery in cancer, foster greater collaboration, and improve the sharing of cancer data.”
“Dogs live in our world. They get all the same diseases we do. They eat our food. They’re exposed to the same environmental pollutants,” Elaine Ostrander, a senior geneticist at the National Institutes of Health (NIH) told Anderson Cooper in a 60 Minutes feature. “But they also have all the same genes that we do. And they have mutations in those genes that make them susceptible to everything you and I get — whether it’s diabetes or cancer or neuromuscular diseases. Everything humans get, dogs get.”
Ostrander said it’s easier to study genes in dogs than in humans because of specific breeding practices that have existed for the last 200 years. Dogs have been bred with an emphasis on creating or preserving distinct traits such as physical features: noses, tails, and sizes. “So that means it’s probably gonna be a really small number of genes responsible for most of the major differences,” Ostrander explained.
Ostrander’s team at the NIH has learned that some physical traits in dogs, such as ear position, hold information that aids research regarding human health.
Ostrander said some of the most hopeful genetic research in dogs involves cancer. Some dog breeds are more susceptible to certain cancers, which allows researchers to locate and isolate the specific genes which cause these cancers.
Osteosarcoma, an aggressive and malignant cancer, affects more than 10,000 dogs in the U.S. annually. It is more rarely found in humans, with only about 1,000 people diagnosed yearly, mostly children and young adults.
Beginning in 2012, University of Pennsylvania professor and veterinarian Dr. Nicola Mason led trials in domestic dogs of an experimental immunotherapy treatment for osteosarcoma. The trial used a bacteria called listeria to fight off cancer. “Listeria…causes food poisoning,” Mason said. “This particular listeria has been genetically modified so that it is far less virulent.”
The listeria had also been altered to contain a specific protein called HER2, which is found in some osteosarcoma cells. Once the bacteria were injected into the dog’s bloodstream, they awakened the animal’s immune system and caused the animal to fall sick. The bacteria also activated immune cells to target cancerous cells.
The first listeria trial in pet dogs yielded positive results, showing the dogs “tolerated” the immunotherapy and that it “significantly increased duration of survival time.”
The FDA approved a phase II clinical trial last year, which uses modified listeria to treat young adults and children who have recurrent osteosarcoma.
The National Cancer Institute is spending more than $20 million to study and analyze cancer samples from pet dogs all over the country. Currently, they oversee comparative oncology trials to improve treatments in humans and dogs.
