Transitional cell carcinomas (TCC) are the most common malignant tumors of the canine urinary tract. Mochizuki et al. (PLoS ONE 2015a, 10(6):e0129534; PLoS ONE 2015b, 10(12):e0144170) identified the BRAF variant V595E in approximately 85% of canine TCC cases by DNA sequencing of TCC tumor cells as well as in prostate carcinoma.
This BRAF variant V595E analysis is a non-invasive and simple tool used to confirm the diagnosis in cases where TCC is suspected. However, it is important to note that only a positive identification of the mutation is valuable, since the variant could never be demonstrated in animals with cystitis, polyp or other urinary bladder neoplasms.
The absence of the BRAF mutation may be due to the fact that the tumor is not caused by a BRAF mutation or that the submitted material did not contain mutated cells. In addition, the tumor might not be a TCC, but a tumor of other origin, a polyp or cystitis.