The domestic cat, a daily companion in millions of homes, could play an unexpected role in the fight against cancer. A new international study has revealed that feline tumors share key genetic alterations with humans, opening the door to better understanding breast cancer and exploring treatments that benefit both human patients and animals.
The research, published in the journal Science and led by the Wellcome Trust Sanger Institute along with the Ontario Veterinary College and the University of Bern, analyzed the DNA of tumors from nearly 500 domestic cats from five countries. The result: genetic mutations that drive cancer development in cats and that coincide with those observed in humans, especially in breast cancer.
Researchers studied around a thousand genes associated with human cancer in 13 different types of feline tumors, comparing them with healthy tissue. The conclusion is clear: many of the genetic changes that cause cancer in cats are comparable to those found in humans and dogs.
The clearest example is in feline mammary carcinomas, a common and aggressive form of cancer in cats. The study identified seven key driver genes when mutated. The most common was FBXW7, altered in over 50% of the analyzed feline tumors. In humans, mutations in this gene are associated with a worse prognosis in breast cancer, suggesting a direct biological parallel between species.
The second most common gene, PIK3CA, appeared in 47% of cat mammary tumors. This same gene is also involved in human breast cancer and is already the target of specific therapies with PI3K inhibitors. In other words: what is tested in cats could help refine treatments in humans, and vice versa.
The work is based on the approach known as One Medicine, which proposes a bidirectional flow of knowledge between human and veterinary medicine. Cats share home, air, and pollutants with their owners, implying that they may be exposed to similar environmental risks that influence cancer development.
This not only opens the door to new oncological treatments for pets but also to better understand how the environment and habits influence the risk of cancer in humans. In fact, the authors suggest that effective therapies in humans could be tested in cats with equivalent tumors and that the results of those trials could guide future clinical studies in people.
The potential impact of these findings is better understood when looking at the numbers. Breast cancer is the most diagnosed tumor in women worldwide, with over 2.3 million new cases per year, according to recent global estimates. In Spain, around 35,000 cases are diagnosed annually, making it the most common cancer among women and one of the main challenges for the healthcare system.
Furthermore, survival has significantly improved thanks to therapeutic advances and early diagnosis, but there is still a great heterogeneity in tumors: some respond well to standard treatments while others show resistance. This is precisely where genetic comparison with feline tumors could be useful in identifying new markers of aggressiveness or therapeutic response.
This is not the first time that domestic animals have contributed to medical advances. Dogs have been key in research on bone cancer and lymphomas, and animal models have allowed the development of immunological therapies that are now applied in human oncology. In the case of cats, their contribution had been more limited due to the lack of large-scale genetic studies, something that this new work is beginning to change.
Historically, comparative medicine has shown that many diseases share biological bases across species. Research in animals has helped understand everything from viral infections to metabolic disorders, and now feline oncology joins that shared scientific map.
One of the most promising findings is that certain chemotherapy drugs were more effective in feline mammary tumors with mutations in FBXW7, at least in tissue samples. Although it still needs to be validated in clinical trials, this data points to personalized therapies that could benefit both cats and human patients.
Researchers also found genetic similarities in blood, lung, skin, bone, gastrointestinal, and central nervous system tumors, suggesting that the parallelism is not limited to breast cancer. According to the authors, this is one of the biggest advances in feline oncology to date and the end of the genetic black box of tumors in cats.
In many European households —and especially in the United Kingdom, where over ten million cats live— these animals are part of everyday life. Now, in addition to companionship, they could offer valuable information to understand why cancer appears and how to better treat it.
Thus, the feline sunbathing on the couch could be unknowingly helping to answer one of the big questions of modern medicine: why some cancers become more aggressive and how to anticipate them. The answer, perhaps, is not only in the human laboratory but also in the genetics of our four-legged companions.