BRAF Mutation Analysis: A Retrospective Evaluation of 8365 Diagnostic Samples with a Special View on Canine Breeds...

The BRAF V595E mutation analysis in canine urothelial carcinomas (UCs) has found its way into routine diagnostics, but no data analysis has been published until now. The present study aimed to estimate the distribution of age, sex, and breed in 8365 canine diagnostic samples submitted for BRAF mutation analysis during 2018-2024. The specimens included 8215 urine samples, 17 cytological, and 133 histopathological specimens, and were submitted in cases of suspected UC, to rule out UC, or for screening purposes. All samples were tested for the BRAF V595E mutation using droplet digital PCR (ddPCR). The data were statistically analysed and logistic regression models (Odds Ratio (OR)) were calculated. Compared to samples from mixed-breed dogs, the specimens from Scottish Terriers (OR: 4.21), Shetland Sheepdogs (OR: 2.65), Beagles (OR: 2.33), Fox Terriers (OR: 1.92), Staffordshire Bull Terriers (OR: 1.86), Magyar Vizslas (OR: 1.77), Chihuahuas (OR: 1.70), and West Highland White Terriers (OR: 1.43) had a significantly increased probability of the presence of BRAF mutation indicating UC. The youngest BRAF-positive dogs of these predisposed breeds (n = 4) were 5 years old. In conclusion, screening tests in predisposed breeds may be recommended from the age of 5 years.