Cancer in dogs and humans share more genetic similarities than previously thought: Study

There are many health benefits to having a dog. Previous research has shown that having a dog can help reduce stress and anxiety. For people who are blind or vision-impaired, a guide dog can provide a person with more independence and mobility. Dogs are also believed to help improve human immune health. They can even sniff out COVID and detect positive cases in schools. And now, according to a recent study published in Scientific Reports, canines can help scientists better understand human cancer and perhaps accelerate future cancer treatments for both dogs and humans.

The study, published by researchers from The Broad Institute of MIT and Harvard, University of Georgia, and the One Health Company, demonstrates that dog and human cancers share more genomic similarities than previously known. Researchers looked at nearly 42,000 genetic mutations found in the tumor samples of 671 pet dogs and compared them to genetic mutations found in 25,000 human tumors.

The results revealed a previously unknown degree of similarity in key genetic mutations. In other words, human cancer has a lot in common with dog cancer.

"The results of this study show the incredible potential of combining canine cancer genomics and big data analysis to save lives on both ends of the leash," said study co-author and One Health Company CEO Christina Lopes in a media statement. "Human cancer research has been moving toward a genomics-based treatment paradigm for decades, but research on canine cancer genomics hasn't kept up."

Specifically, the study identified 18 genetic mutations that are likely a primary driver of the cancer in canine patients, eight of which overlapped with so-called "hotspots" in human cancers. For example, the most commonly mutated gene in human cancers, called TP53, is the most commonly mutated gene in canines, too. In the study, it was found to be in 25 percent of all the analyzed canine tumors which spanned across 96 breeds.

Mutations to the TP53 gene cause cancer cells to grow and spread and are most commonly associated with leukemia, breast cancer, bone cancer and soft tissue sarcomas. Hypothetically, it's possible that treatments used on humans to target this genetic mutation could be used on dogs and vice versa — and that's the goal.

By demonstrating that there are similarities between dog and human cancer, the hope is that treatment data from canine cancer patients can be used to accelerate preparation and delivery on cancer treatments that can be used for both dogs and humans. Historically, developing cancer treatment is a long and expensive process. An estimated 97 percent of new cancer drugs never make it to market.

"This paper shows that the genomic drivers of cancer in dogs are quite similar to the genomic drivers of cancer in people," Dr. Gerald Post, the Chief Medical Officer at One Health told Salon in an interview. "And again, these are naturally occurring cancers in animals, humans and dogs with intact immune systems."

Post emphasized that after being in the business of oncology for 30 years, he's never seen more "acceleration" and a more optimistic outlook in regards to development than he has in the field of comparative oncology. Cancer is the leading cause of death for dogs, and after heart disease, the second leading cause of death for Americans. Indeed, the study's findings emphasize how a growing field of research called comparative oncology — which means using naturally occurring cancers in animals as models for human disease — can change the future of cancer diagnoses and treatments.

In the past, researchers have looked to data from canine cancer patients to accelerate the development of more than 10 cancer drugs at a lower cost, as Wired reported in 2019. Post said genomics has long been "the missing piece in the puzzle." But now, thanks to this study, it could help advance research and treatments for both dogs and humans by providing more people with a more robust database.

"Now people can look at a cancer and say, 'oh, this cancer looks like a cancer in a human,' and 'it also has the exact same genetic mutation that this cancer in people have, let's see what therapies work here,'" Post said, giving an example for how vets could use human cancer treatments on dogs. "[And] we've given human cancer researchers a tool to evaluate their drugs and dogs with specific cancers with specific mutations, and so it's just wonderful. It's rare in science to have a win-win-win scenario — a win for pets, a win for people and a win for pet parents."