Signalment data and ddPCR assay values for the sample cohort.

The table lists the owner-reported breed and sex of dogs included in the study (* indicates unknown sex), in addition to the age of the dog at the time of sample submission. The sample ID prefix UD denotes specimens in which the BRAF V595E variant was undetected, and the prefix POS denotes samples that tested positive for this variant by ddPCR analysis. For the 28 UDV595E cases, the notation H/C after the sample name denotes that the diagnosis of UC was validated using conventional histopathology and/or cytology evaluation of tumor tissue (n = 7 cases). The notation US indicates the presence of a bladder mass on ultrasonography, with clinical signs and progression consistent with canine UC (n = 8 cases). Where detected, the VAF (from WES analysis) and FA (from ddPCR analysis) of the variant is shown as a percentage. The DT represents the lowest variant FA that was capable of being detected by the assay for each individual sample [5]. This value provides confidence that UDV595E specimens are classified correctly down to a level of no greater than a single mutant allele among 1000 total alleles. The final two columns indicate the copy number ratio data derived using the UC CNA ddPCR assay. All 36 samples were classified as ‘positive’ for both DNA copy number signatures since they exceed the ratio threshold of 1.20 [21].