A large-scale genetic study of cat tumors has revealed significant similarities with human cancers, potentially opening new paths for cancer treatment in both species. The research, conducted by an international team including scientists from the University of Guelph, the Wellcome Sanger Institute, and the University of Bern, analyzed tumor samples from nearly 500 domestic cats across five countries. The findings, published in Science, suggest that many of the genetic changes driving cancer in cats are also found in human cancers. The study identified key genetic mutations in cat cancers that are also associated with human cancers, including the FBXW7 gene, which was found to be mutated in more than 50 percent of the cat mammary tumors examined. In humans, mutations in the FBXW7 gene in breast cancer are associated with a worse prognosis, a finding that parallels the changes seen in cats. Researchers noted that the similarities between cat and human cancers may be particularly useful because domestic cats often live in environments similar to those of humans, potentially exposing them to the same environmental factors that influence cancer risk. This shared environment could help researchers better understand how genetics and the surrounding environment interact in cancer development. The study also highlights the potential for precision oncology in both cats and humans, where genetic information could help identify more effective treatments for specific tumors. The research team found that certain chemotherapy drugs were more effective against cat mammary tumors with the mutated FBXW7 gene, though further studies are needed to determine if this approach would work in living cats or humans. The findings support the One Medicine approach, which emphasizes the mutual benefits of human and veterinary medicine. Cancer treatments developed for humans could be evaluated in cats with naturally occurring tumors, while discoveries made in feline cancer studies could inform future human research. The study also provides a foundation for the next stage of feline cancer research, aiming to bring more personalized cancer care to cats. The research was funded in part by the EveryCat Health Foundation, the CVS Group, Wellcome, the Natural Sciences and Engineering Research Council of Canada, and the Swiss National Science Foundation.