While exploring the genetic factors that make golden retrievers more susceptible to cancer than other dog breeds, researchers discovered a gene linked to longevity that is linked to a gene that causes human cancer cells to grow rapidly. This discovery has the potential to help us and our furry best friends.

Outgoing, trustworthy, helpful, and relatively easy to train. These characteristics make Golden Retrievers popular among dog owners. Unfortunately, naturally occurring cancer is the leading cause of death in pet dogs, and Golden Retrievers fall short in this regard, with a 65% chance of dying from cancer.

Researchers at the University of California, Davis, studied the genetic makeup of golden retrievers to determine whether certain genetic factors contribute to their survival. However, they were not studying genes related to cancer, but genes related to longevity.

"We think most golden retrievers have a genetic predisposition to cancer, but if some of them live to be 14, 15 or 16 years old, we think there may be another genetic factor that helps them mitigate the effects of bad genes, and the gene that stands out to us is HER4," said Robert Rebhun, first and corresponding author of the study.

HER4, also known as ERBB4, is a member of the human epidermal growth factor (EGF) receptor family. It is in the same family as HER2, a human gene known to make cancer cells grow rapidly.

More than 300 golden retrievers participated in the study. The researchers compared DNA in blood samples from dogs that were alive at age 14 and dogs that died before they were 12 years old. They found that dogs with certain variants of the HER4 gene lived longer, on average, to 13.5 years old, while dogs without the gene only lived to 11.6 years old.

Danika Bannasch, co-corresponding author of the study, said: "Nearly two years is a significant difference in a dog's lifespan. Don't we want our beloved pets to live two more years? A golden retriever's two-year lifespan is approximately 15-20% longer, which is equivalent to 12-14 years in humans."

The researchers also found that genetic variation appeared to be most important for female dogs' longevity compared with male dogs. HER4 has been shown to interact with hormones such as estrogen and may also play a role in dealing with environmental toxins. These findings are just one piece of the puzzle as to why golden retrievers are more susceptible to cancer.

"There are probably many genes involved, but the fact that genes associated with longevity are also genes associated with cancer is of great interest to us," Bannasch said. "Dogs develop many of the same types of cancers as humans, so this discovery was also important to us."

"If we find that this variant in HER4 plays an important role in the development or progression of cancer in golden retrievers, or that it actually alters cancer risk in people who are susceptible to this cancer, then this could potentially be used in future cancer research in humans," Rebhun said.

The next step for the researchers is to study a larger population of golden retrievers to see if the findings can be replicated and to discover how this genetic variation affects gene expression or function.

The research was published in the journal GeroScience.