August 7, 2018 – Dog-breed susceptibility to certain cancers has been recognized for years in the veterinary community, and certainly suspected by owners of certain breeds. But understanding the relationship (if any) between inherited traits and the likelihood of developing cancers has been elusive. A little bit of MADGiC, though, might make it possible to predict who would be at greater risk for developing cancer.
Three Morris Animal Foundation-funded researchers recently got a little closer to making this a reality in a project dubbed the MADGiC study. The study is helping predict cancer likelihood through genetic testing – testing that also might reveal potential risks for different types of cancer. With this knowledge, the risk of cancer might be reduced by early identification and informed breeding practices. That means less suffering of pets at risk for cancer.
Dr. Kerstin Lindblad-Toh, Broad Institute and Uppsala University; Dr. Jaime Modiano, University of Minnesota; and Dr. Matthew Breen, North Carolina State University, have discovered a potential link between certain mutations in the DNA of golden retrievers and risk of future cancer development.
Their three-year, $1 million project examined genetic traits associated with risk and progression of two of the most common and deadliest cancers diagnosed in golden retrievers – hemangiosarcoma and lymphoma. They uncovered two specific gene regions that predispose golden retrievers to both cancers. This finding suggests that mutations in these regions could explain 20 percent to 50 percent of the total risk for lymphoma and hemangiosarcoma in this breed, representing a significant number of cancer diagnoses.
What might this research mean for dog owners and veterinarians?
“The immediate next step is to validate the presence of these risk factors and their association with hemangiosarcoma and lymphoma in independent populations of golden retrievers,” Dr. Modiano said. “This is necessary to enable development of tests that could inform breeding decisions.”
Now that candidate genetic mutations have been identified, researchers need to test more golden retrievers with and without cancer, and see if these observations remain valid in the larger population. Once validated, a genetic test can be developed to identify individuals at higher risk of disease (like breast cancer screening tests in women that look for the BRCA1 and BRCA2 gene mutations), and guide breeders in selecting individuals for breeding programs.
Any data uncovered in the current study might eventually be applicable to other dog breeds, and possibly mixed-breed dogs, too. When embarking on genetic research, scientists often focus first on a single breed because it cuts out “genetic noise” – multiple versions of the same genetic material that is common in mixed-breed dogs. Eliminating the noise allows them to pinpoint genetic regions and mutations associated with disease more quickly.
Once researchers narrow down the genetic region of interest, they can start examining other dog breeds to look for the same change. This process of genetic testing can take years to complete, but once done, it can be an invaluable tool not only for diagnosis, but as a guide for treatment targets. Once unthinkable, it could be MADGiC indeed to identify cancer risk in dogs!