This study aimed to characterize receptor tyrosine kinase (RTK) expression and B-RAF mutations in a canine TCC tissue sample and to investigate the prognostic and therapeutic relevance of B-RAF mutations in ctDNA serially obtained from blood samples of a dog with metastatic urethral TCC harboring the B-RAF V595E mutation, that received third-line treatment with sorafenib. This evidence concerns the gene NTRK1 and tarsal-carpal coalition syndrome.