Peer-reviewed veterinary case report
No link between dog bladder DNA mutations and city water contaminants
By O'Brien, Janice et al.·Published in Veterinary and comparative oncology·2026·Department of Population Health Sciences, United States·View original on PubMed →
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Original publication title: Canine Urothelial DNA Mutations Are Not Associated With Total Trihalomethanes Concentrations in Municipal Drinking Water.
- Species:
- dog
Plain-English summary
A study looked at dogs living in Las Vegas and Reno to see if drinking water contaminants called total trihalomethanes (TTHMs) were linked to mutations that could lead to bladder cancer. While dogs in Las Vegas had a higher chance of showing these mutations compared to those in Reno, the researchers found no direct connection to the TTHM levels in the water. Instead, factors like age, whether the dog was neutered, and certain breeds known to be at higher risk for bladder cancer were more significant. This suggests that other environmental factors might play a role in these mutations. If you're concerned about your dog's risk, especially if they belong to a high-risk breed, it's a good idea to discuss this with your veterinarian.
Abstract
Contaminants in municipal drinking water, specifically total trihalomethanes (TTHMs), are mutagenic. Exposures to TTHMs have been associated with urothelial carcinoma (UC) in both people and dogs. Mutations in the BRAF gene and other genomic copy number aberrations detected in voided urothelial cells with commercial CADET BRAF and BRAF-PLUS tests have also been associated with the presence of UC in dogs. However, it is not known whether these urothelial mutations can be linked to TTHM exposures in dogs. The objectives of this ecological study were to compare the incidence of detected urinary BRAF mutations or genomic copy number aberrations in dogs residing in a city with relatively high drinking water TTHMs (Las Vegas, NV) to a city with significantly lower TTHMs (Reno, NV), and to expand the study group to include BRAF and BRAF-PLUS test results and municipal drinking water TTHM concentrations by zip code across the United States. Dogs living in Las Vegas had a higher relative risk of urothelial mutations compared to dogs living in Reno (RR 2.52; 95% CI, 1.77-3.38; p < 0.0001). However, this risk could not be attributed to higher municipal drinking water TTHMs. Across the United States, the population-adjusted incidence of urothelial mutations in voided urine was not associated with municipal water TTHMs, but was instead associated in cross-sectional analyses with age, neutered status, higher regional test submission rates and previously reported high-risk breeds for UC (Scottish terriers, West Highland white terriers, Shetland sheepdogs, beagles and wirehaired fox terriers). The higher RR for a positive BRAF or BRAF-PLUS test in Las Vegas versus Reno could be solely due to higher test submission rates (2.97 versus 0.97 per 1000 dogs) but could also reflect other environmental exposures not considered in this study.
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Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/41816851/