Cat Tumors May Offer New Clues for Treating Human Cancer, Study Finds

A large genetic study of nearly 500 domestic cats has found that many of the genes driving cancer in cats are also involved in human cancers, giving scientists new clues about how tumors develop and how some treatments may work. The international study, published in Science and involving researchers from Canada, Switzerland and the United Kingdom, analyzed cat tumor samples collected across five countries.

The research could be important because cats naturally develop many types of cancer while living in the same environments as people. Instead of looking at cancer only in laboratory models, scientists can study tumors that develop naturally in animals and compare their genetic changes with those found in humans.

Cat tumors share important cancer genes with humans

Researchers genetically examined tumor samples from almost 500 domestic cats to identify mutations that help cancer develop and grow. The study represents one of the largest efforts so far to map the genetic causes of feline cancer.

One of the strongest similarities appeared in mammary cancer, a cancer affecting breast tissue. More than 50% of the cat mammary tumors studied had mutations in a gene called FBXW7, making it the most common cancer-driving gene identified in those tumors.

The same gene is also involved in human breast cancer. In people, FBXW7 mutations have been associated with a worse prognosis, showing a notable genetic similarity between the cancers in the two species.

Researchers also found similarities involving cancers of the blood, bones, lungs, skin, gastrointestinal system and central nervous system.

Dr. Geoffrey Wood, a pathobiology professor at the University of Guelph and co-senior author of the study, said scientists previously knew surprisingly little about the genetic basis of cancer in cats.

“Despite domestic cats being common pets, there was very little known about the genetics of cancer in these animals,” Wood said, “until now.”

Drug response could be another important clue

The study did more than identify similar cancer genes. Researchers also tested how certain chemotherapy drugs affected cat mammary tumor tissue carrying different genetic changes.

They found that some chemotherapy drugs were more effective against cat mammary tumors with the mutated FBXW7 gene. The result was seen in tissue samples, however, so it does not yet prove that the same treatment would work in living cats or humans.

Still, the finding points toward a possible use for cats in precision cancer research. Precision oncology means using the genetic features of a tumor to help determine which treatment may work best, rather than treating every tumor of the same general type in exactly the same way.

Dr. Sven Rottenberg, a co-senior author from the University of Bern, said the large collection of donated tissue made it possible to examine treatment responses at a scale that had not previously been possible.

“Having access to such a large set of donated tissues allowed us to assess drug responses across tumour types,” Rottenberg said, “in a way that hasn’t been possible at this scale before.”

Why cats could become useful cancer research models

Cats may provide researchers with a different way to study cancer because their tumors develop naturally rather than being deliberately created for an experiment.

Domestic cats also share many aspects of daily life with their owners. They can be exposed to some of the same environmental conditions, which could allow scientists to investigate how genetics and environmental factors interact in cancer development.

Wood said the findings could eventually help researchers study cancer across species.

“This study can help us understand more about why cancer develops in cats and humans, how the world around us influences cancer risk, and possibly find new ways to prevent and treat it,” Wood said.

The researchers used tissue samples that veterinarians had already collected during routine diagnostic work. They then sequenced the DNA in those samples and compared the genetic changes across different types of feline tumors.

The study also supports a research strategy known as “One Medicine,” which encourages human and veterinary medicine to share knowledge. Treatments developed for people could potentially be studied in cats, while findings from feline cancer trials could eventually provide information useful for human cancer research.

The findings are a starting point, not a new cancer treatment

The study does not show that cats can directly provide a new cancer cure for people. The drug-response findings were made in tissue samples, and additional research would be needed to determine whether those genetic patterns can reliably predict treatment responses in living animals or humans.

Researchers say the newly created genetic resource could instead provide a foundation for future studies of feline cancer and precision treatment.

Dr. Louise Van Der Weyden, senior author at the Wellcome Sanger Institute, said the work could help move feline cancer research toward more personalized diagnosis and treatment.

“We can now begin to take the next steps forward towards precision feline oncology, to catch up with the diagnostic and therapeutic options that are available for dogs with cancer, and ultimately one day, humans,” Van Der Weyden said.

The broader significance of the study is that a pet cancer diagnosis may contain information useful beyond veterinary medicine. By comparing naturally occurring cancers across cats, dogs and humans, researchers may be able to identify common genetic changes and investigate why certain tumors respond differently to treatment.