Cats give genetic clues to better cancer treatments

Similarities between pet and human tumours suggest new ideas for targeting both

Household animal species are of particular interest because they are exposed to some of the same environmental risks as their human companions

Domestic cats have emerged as unlikely allies in the fight against human cancers, after scientists found close similarities between genetic changes that drive the deadly disease in both species.

The discoveries from the first large-scale DNA study of feline tumours open up new ideas for treatments for people and pets, researchers from the UK’s Wellcome Sanger Institute said.

Scientists are increasingly focusing on genetic lessons from animals that are prone to cancers or unusually resilient to them. Household species are of particular interest because they are exposed to some of the same environmental risks as their human companions.

“By comparing cancer genomics across different species, we gain a greater understanding of what causes the disease,” said Bailey Francis, a Wellcome Sanger researcher and co-first author of a paper published in the journal Science on Thursday. “This could help experts in the veterinary field as well as those studying cancer in humans.”

The Wellcome Sanger researchers and colleagues from countries including Canada and Switzerland examined 13 cat cancer types using tissue samples collected by vets from almost 500 domestic animals across five countries.

They sequenced DNA from tumours and healthy tissues to look for about 1,000 genes that are associated with cancer in people. The felines showed similar genetic mutations to humans in cases of blood, bone, lung, skin, gastrointestinal and central nervous system tumours.

One of the most intriguing findings was for cat breast cancers, more than half of which showed a mutation in a gene called FBXW7. The change is far rarer in human mammary cancers, but the prognosis for the sufferer is worse when it is present.

The researchers found that the chemotherapeutic drugs vincristine and vinorelbine, used to treat diseases such as leukaemia, curbed the growth of the FBXW7-mutated tumours in cat tissues.

This suggested an initial test of the drugs’ effectiveness against breast cancer could be done in felines, as a trial in people would be hard to organise because of the FBXW7 mutation’s relative scarcity.

“Since vincristine is already in use in both human and veterinary clinics, it offers the opportunity for use in a clinical trial in felines with mammary cancer, with the results being extremely informative for human breast cancer patients,” said Louise Van Der Weyden, a cancer genetics expert at the Wellcome Sanger Institute and senior author of the cat paper.

The feline cancer work was an interesting contribution to the expanding field of “comparative oncology” between humans and other animals, said Trevor Graham, professor of genomics and evolution at The Institute of Cancer Research, London.
Geoff Wood and Arlene Khachadoorian in lab coats seated beside a microscope in a laboratory.Geoff Wood, left, and Arlene Khachadoorian from Ontario Veterinary College at the University of Guelph in Canada are two of the authors of the paper
Other researchers are examining whether the suspected genetic reasons for elephants’ striking resistance to malignant tumours can be translated into treatments for humans.

“Understanding the mechanisms that make different species better — or worse — at suppressing cancer may give us clues about how to prevent or treat human disease,” Graham said.

“Humans and animals have a shared evolutionary history, so there is much we can potentially learn by studying cancers in other animals that could eventually benefit human patients — and vice versa.”