EP300 and in situ carcinoma: Shared (in pTa HG/papillary pT1 HG and CIS) frequent alterations in the chromatin-modifying genes KDM6A, ARID1A, CREBBP and EP300 should encourage clinical testing of inhibitors of EZH2 [31], PARP [32] and EP300/CREBBP bromodomain [33] for high-risk NMIBC, having either entered clinical trials (https://clinicaltrials.gov/; Oct 25, 2019; NCT03854474, NCT03568656) or being (in the case of PARP inhibitors) FDA-approved.