Largest study of cat cancers finds surprising similarities to human cancers, pointing to new treatments for multiple species
The genetics of cat tumours are no longer a “black box,” researchers say, thanks to a new study considered one of the largest developments in feline cancer research.
Published in the journal Science, the study marks the first time that cat cancers have been genetically profiled at a large scale. It could help our understanding of cancer in both humans and animals, forming the basis for a freely available resource for other scientists working on feline cancer genetics.
Cancer is one of the leading causes of illness and death in cats.
But it has been relatively unexplored, says Dr. Geoffrey Wood, University of Guelph pathobiology professor and co-senior author of the international study.
“Despite domestic cats being common pets, there was very little known about the genetics of cancer in these animals,” Wood says, “until now.”
Cancer-driving genes are similar between cats and humans
Analyzing tumour samples from almost 500 domestic cats across five countries, researchers explored the genetic changes that drive cancer formation in cats, finding a remarkable number of similarities between those in human and dog cancers.
They identified specific driver genes that lead to the development of certain cancers, including aggressive mammary cancers.
The most common driver gene in cat mammary cancer was FBXW7. Over 50 per cent of the cat tumours had a mutation in this gene.
In humans, mutations in the FBXW7 gene in breast cancer are associated with worse prognosis – paralleling the change seen in cats.
Other similarities to human driver mutations were seen across blood, bone, lung, skin, gastrointestinal and central nervous system tumours.
As cats are exposed to many of the same environmental cancer risks as their owners, some causes could be partly shared.
“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,” says Wood.
To their excitement, researchers also found certain chemotherapy drugs were more effective in the cat mammary tumours with the mutated FBXW7 gene. While observed only in tissue samples, this finding may open new avenues of therapy for breast cancer across species.
“Having access to such a large set of donated tissues allowed us to assess drug responses across tumour types,” says Dr. Sven Rottenberg, co-senior author at the University of Bern, “in a way that hasn’t been possible at this scale before.”
Bailey Francis, co-first author at the Wellcome Sanger Institute, adds that the research may benefits dogs as well.
“When knowledge and data flows between different disciplines, we can all benefit.”
‘One Medicine’ approach calls for research between disciplines, species
Collaborating across the Wellcome Sanger Institute, U of G’s Ontario Veterinary College, the University of Bern and other institutes, researchers sequenced DNA from tissue samples that had already been collected by veterinarians for diagnostic purposes.
The findings suggest that therapeutic approaches in humans could be trialled in cats; likewise, information learned from cancer clinical trials in domestic cats could be used to inform human clinical trials.
This is known as the One Medicine approach, which promotes the two-way flow of data and knowledge between medical and veterinary disciplines to benefit both human and animal health.
Dr. Louise Van Der Weyden, senior author at the Wellcome Sanger Institute, points to areas of future research.
“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.”
This research was funded in part by EveryCat Health Foundation, the CVS Group, Wellcome, the Natural Sciences and Engineering Research Council of Canada and the Swiss National Science Foundation. A full acknowledgement list is found in the publication.