Dogs may hold key to human cancers

Siberian husky exhibiting heterochromia. (Photo by Przykuta, corrected by Pharaoh Hound, CC BY-SA 3.0, via Wikimedia Commons

The keys to unlocking some of nature’s most intriguing puzzles about cancer may have been walking beside humans for years.

Because of genetic similarities that make them more susceptible to the disease, purebred dogs can aid researchers in the quest to better understand human cancers, Matthew Breen, professor of genomics at the North Carolina State University School of Veterinary Medicine said at CASW’s New Horizons in Science, part of the ScienceWriters2013 meeting in Gainesville, FL.

“How many people own a dog?” Breen asked the science writers in the auditorium, with nearly everyone raising a hand.

Cancer prevalent in dogs

When Breen asked if these owners had lost a dog to cancer, more than half of the hands stayed in the air.

Cancer is a major killer of dogs, explained Breen. Each year, about 4.2 million dogs are diagnosed with cancer, compared to 1.5 million people. Additionally, dogs have 2.5 times the number of cancers and more than 11 times the overall rate.

The statistics are disheartening, but caused by a variety of factors, Breen said, most of which make sense after studying the history of purebred dogs.

One has to travel back thousands of years ago, Breen said, when dogs used to wander around, mating with each other at will. As human society evolved, some people “got richer,” Breen said, and started to specifically breed certain kinds of dogs because they liked the way they looked.

Over time, certain breeds became extremely genetically similar, which made them more prone to diseases like cancer, Breen said. As a result, it’s easier for researchers to identify genetic abnormalities in dogs with cancer and then translate the findings to humans.

Humans and dogs share cancers

“I don’t want you to think of them as separate species,” Breen said. “Cancer is now bidirectional.

“When we look at bone cancer in dogs, and bone cancer in people, we cannot separate the two,” he continued.

Specifically, Breen has used dog tumors to narrow down the search for genetic disruptions associated with cancers in humans. For his studies, he has relied on samples submitted by pet owners, at no harm to the animal.

“The worst we ever do is take a blood sample or a teeth swab,” he explained.

Ultimately, Breen believes cancer cannot be cured. But there is hope, he said, in turning it into a treatable disease by “studying all corners of the genome,” dog or human.

“I believe we’ll be able to diagnose it sooner,” Breen said. “We’ll be able to treat it sooner.”

Zack Peterson is a junior at the University of Florida studying journalism and English. He is a correspondent for The Gainesville Sun and WUFT News and enjoys storytelling. This past summer, he interned at a regional daily newspaper covering the towns and villages clustered around Dartmouth College. You can follow him on Twitter @zackpeterson918, email him at, or check out more of his work at