The first study of multiple cancer types in cats has identified genetic changes that could help treat the condition in humans and animals.
By analysing different types of tumours from almost 500 pet cats across five countries, experts at the Wellcome Sanger Institute, the Ontario Veterinary College in Canada, the University of Bern, and their collaborators, discovered the genetic changes that drive cancer formation in cats and found similarities between these and ones seen in humans.
Cats are exposed to some of the same environmental cancer risks as their owners, which means that some causes could, at least in part, be shared. By sequencing DNA from tissue samples that had already been collected by the vet for diagnostic purposes, this research, published today (19 February) in Science, highlights certain genetic changes commonly found in cat cancers mirror those seen in human cancers. For example, they found similarities between feline mammary cancers and human breast cancers.
Overall, this research suggests that there are multiple genetic changes that could be explored further, through genomics and clinical trials, to determine if it is possible to develop cancer treatments that target these changes in both cats and potentially humans.
Almost a quarter of all UK households own at least one cat, and with over 10 million cats living in the UK they are now about as popular as dogs as pets1. Cancer is one of the leading causes of illness and death in cats2, however very little is known about how this develops.
This new research is the first time that cat cancer tumours have been genetically profiled at scale and has created a freely available resource for all future feline cancer genomics work.
In the new study, researchers, including those at the Sanger Institute, looked for around 1,000 human cancer-associated genes in both tumours and healthy tissue samples from almost 500 pet cats. This included 13 different types of cat cancer and allowed them to compare the genetic changes to those seen in human and dog cancers.
They showed that for some cancer types, the genetic changes that drive cancer development in domestic cats are comparable to those seen in humans.
For example, mammary carcinomas are a common and aggressive type of cancer in cats. This research identified seven driver genes that led to the development of cancer when mutated. The most common driver gene was FBXW7 and over 50 per cent of the cat tumours had a change in this gene. In humans, changes in the FBXW7 gene in breast cancer tumours are associated with worse prognosis, which parallels what is seen in cats.
Excitingly, this study found that certain chemotherapy drugs were more effective in the cat mammary tumours with changes in the FBXW7 gene. While this was conducted in tissue samples, and requires further investigation, this may offer a potential avenue of therapy for both cats with mammary carcinoma and human breast cancer patients3.
The second most common driver gene was PIK3CA, seen in 47 per cent of cat mammary carcinoma tumours. This is also a genetic change found in human breast cancer, where it is treated with PI3K inhibitors.
Similarities to human driver mutations were also seen across blood, bone, lung, skin, gastro-intestinal, and central nervous system tumours. Future research exploring these genetic changes could lead to new knowledge and possibly therapies for cancers across the species.
For example, the researchers suggest that successful therapeutic approaches in humans could then be trialled in cats and that information we learn from 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.
Bailey Francis, co-first author at the Wellcome Sanger Institute, 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."
Professor Geoffrey Wood, co-senior author at the Ontario Veterinary College, 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. This 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."
Professor Sven Rottenberg, co-senior author at the University of Bern, Switzerland, said: "Having access to such a large set of donated tissues allowed us to assess drug responses across tumour 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".
Dr Louise Van Der Weyden, senior author at the Wellcome Sanger Institute, said: "This is one of the biggest ever developments in feline oncology and means the genetics of domestic cat tumours are no longer a 'black box'. 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."
