TET1 and urinary bladder cancer: Two of the five metastatic cases in our cohort showed mutations that were predicted to inactivate genes involved in epigenetic regulation, namely BAP1, KDM6A and TET1. Mutations of BAP1 and KDM6A were concurrent in the primary and one metastatic lesion of case SPN13, and co‐occurring mutations of these genes have already been reported in bladder cancer 26.