A somatic point mutation in the BRAF gene (BRAFV595E), which is homologous to the human BRAFV600E mutation, is present in over 70% of dogs with bladder and prostate cancers.38 We have recently shown that BRAFV595E mutation induces CCL17 production and contributes to Treg recruitment in dogs with bladder cancer.36 Thus, we investigated whether BRAFV595E mutation influences tumor-infiltrating Tregs or the CCL17–CCR4 axis in dogs with prostate cancer. Here, CCR4 is linked to urinary bladder carcinoma.