Certain dogs may be more susceptible than others to developing environmentally associated cancers. Morris Animal Foundation-funded researchers at the University of Wisconsin-Madison School of Veterinary Medicine are studying how exposure to common environmental chemicals, like those found in tobacco smoke and yard products, and individual genetic differences in response to them, put dogs at risk for common cancers. Information gained will help form strategies to prevent cancer in dogs, including possible avoidance and dietary modifications.
When dogs or humans are exposed to toxic chemicals in the environment, glutathione-S-transferase (GST) enzymes in the liver help neutralize those chemicals. Due to genetic variations in GST enzymes, people vary in their capacity to deactivate environmental hazards. If these individuals ingest or inhale toxic chemicals, this inability can result in cancer development over repeated exposures. This is why two different people exposed to the same chemical can have a different risk for developing cancer.
“We want to know if the same thing is true for dogs and how they react differently on a genetic level,” said Lauren Trepanier, professor and assistant dean for clinical and translational research at the UW School of Veterinary Medicine and principal investigator on the study. “If we can better understand what sort of chronic household exposures are important in dogs, then we can do a better job of counteracting them and maybe decreasing the incidence of certain cancers.”
For their study, the team is replicating four major forms of GST enzymes and then incubating them with potential carcinogens to see if the enzymes react with those substances. Chemicals of interest include acrolein, found in air pollution, heat-treated foods and tobacco smoke. Another substance of interest is a form of 2,4-D, an herbicide associated with lymphoma and bladder cancer in both dogs and people.
“If we can better understand what sort of chronic household exposures are important in dogs, then we can do a better job of counteracting them and maybe decreasing the incidence of certain cancers.”
“The study’s findings could eventually allow us to identify dogs in a population that might be susceptible to certain cancers based on their enzyme profile,” said Janet Patterson-Kane, Morris Animal Foundation chief scientific officer. “We may not have complete control over the toxic chemicals we expose our dogs to, but information like this could help us give them the longest, healthiest lives we can.”
Trepanier and her team also are comparing toxic chemical levels in the urine of dogs with and without bladder cancer, as well as in urine samples from their owners who share the same households. The goal is to determine if having a dog diagnosed with bladder cancer indicates the owner may be exposed to more chemicals in the environment that are relevant to human health.
Morris Animal Foundation, headquartered in Denver, is one of the largest nonprofit animal health research organizations in the world, funding more than $155 million in studies across a broad range of species.