To date, several BrD family members (KAT2A, EP300, TAF1, BRPF1, KMT2A, SMARCA4, BAZ1B, BAZ2A, ATAD2, BRD4, TRIM24, TRIM28, and ZMYND8) were recognized and confirmed (mechanistically, at the molecular level) as positive regulators/mediators of cancer stemness, while for the SMARCA2 protein—mostly negative roles in CSC maintenance were reported (Figure 1). This evidence concerns the gene EP300 and cancer.