Environmental Exposures and Canine Bladder Cancer: A Case Control Study Using Silicone Passive Samplers

Area of Science:

• Environmental Health
• Veterinary Oncology
• Toxicology

Background:

• Pet dogs share human environments, offering insights into environmental health impacts.
• Canine urothelial carcinoma, a cancer of the urinary tract, shares similarities with human bladder cancer.
• Dogs develop cancer more quickly than humans, serving as a valuable model for environmental exposure studies.

Purpose of the Study:

• To assess and quantify environmental chemical exposures in pet dogs with high risk of urothelial carcinoma.
• To identify specific chemical contaminants associated with increased cancer risk in dogs.
• To validate the use of pet dogs as models for studying environmental contributions to cancer.

Main Methods:

• A case-control study involving dogs with (cases) and without (controls) a specific BRAF mutation linked to urothelial carcinoma.
• Use of silicone samplers worn by dogs for five days to capture environmental chemical exposures.
• Analysis of samplers using targeted and suspect screening (nontargeted) mass spectrometry methods.

Main Results:

• 39 out of 115 targeted chemicals were detected in over 50% of dog samplers.
• Cases showed significantly higher exposure levels (2-3x) to BDE-47, BDE-99, anthracene, and benzyl butyl phthalate.
• Suspect screening revealed cases were exposed to a greater number of chemicals, with 25 chemical features significantly higher than controls.

Conclusions:

• This study provides the most extensive quantification to date of contaminant exposures linked to canine urothelial carcinoma.
• Findings suggest specific environmental chemicals are associated with increased risk of this cancer in dogs.
• Pet dogs serve as effective models for investigating environmental factors contributing to cancer development, benefiting both human and veterinary health.