How could cats help cure cancer?

By Stephen Beech

Cats could hold the key to curing breast cancer and other deadly forms of the disease, suggests new research.

The first study of multiple cancer types in cats has identified genetic changes that could help treat the condition in both humans and animals - including dogs, say scientists.

Researchers found "surprising" similarities to human cancers, pointing to new treatments.

The international study, published in the journal Science, is the first time that cat cancers have been genetically profiled on a large scale.

Co-senior author Professor Geoffrey Wood explained that cancer is one of the leading causes of illness and death in cats, but it has been relatively unexplored.

Almost one-in-four UK households own at least one cat, and with over 10 million cats living in Britain they are now almost as popular as dogs as pets.

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

"Our household pets share the same spaces as us, meaning that they are also exposed to the same environmental factors that we are."

Analyzing tumor samples from almost 500 domestic cats across five countries, the research team explored the genetic changes that drive cancer formation in cats.

They identified specific driver genes that lead to the development of certain cancers, including aggressive mammary cancers.

Wood said the most common driver gene in cat mammary cancer was FBXW7, with more than half of the cat tumors having a mutation in that gene.

In humans, mutations in the FBXW7 gene in breast cancer are associated with worse prognosis – paralleling the change seen in cats.

The second most common driver gene was PIK3CA, seen in 47% of cat mammary carcinoma tumors.

It is also a genetic change found in human breast cancer, where it is treated with PI3K inhibitors.

Other similarities to human driver mutations were seen across blood, bone, lung, skin, gastrointestinal and central nervous system tumors.

As cats are exposed to many of the same environmental cancer risks as their owners, the researchers believe some causes could be partly shared.

Wood said: “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."

The team also found certain chemotherapy drugs were more effective in the cat mammary tumors with the mutated FBXW7 gene.

While observed only in tissue samples, the researchers say the discovery may open new avenues of therapy for breast cancer across species.

Co-senior author Dr. Sven Rottenberg, from the University of Bern in Switzerland, said: “Having access to such a large set of donated tissues allowed us to assess drug responses across tumor types in a way that hasn’t been possible at this scale before.

"This is a powerful tool to help us identify potential novel therapeutic options that we hope will translate to the clinic one day, for both cats and humans”

Co-first author Bailey Francis, of the Wellcome Sanger Institute, Cambridgeshire, says the research may also benefits dogs.

He said: “By comparing cancer genomics across different species, we gain a greater understanding of what causes cancer.

"One of our major findings was that the genetic changes in cat cancer are similar to some that are seen in humans and dogs.

"This could help experts in the veterinary field as well as those studying cancer in humans, showing that when knowledge and data flows between different disciplines, we can all benefit.”

The research team sequenced DNA from tissue samples that had already been collected by vets for diagnostic purposes.

The findings suggest that therapeutic approaches in humans could be trialled in cats.

And information learned from cancer clinical trials in domestic cats could be used to inform human clinical trials.

Senior author Dr. Louise Van Der Weyden, also of the Wellcome Sanger Institute, said: “This is one of the biggest ever developments in feline oncology and means the genetics of domestic cat tumors are no longer a ‘black box’."

She added: "We can now begin to take the next steps forwards 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.”