EP300 and neoplasm: Immunohistochemistry (IHC) staining and western blotting of tumor xenografts 5 days post treatment confirmed significant downregulation of p300/CBP, AR, PSA, MYC, Ki67, CCND1, NKX3-1, CITED2, H3K27ac and H2BK20ac (Fig. 6d and Extended Data Fig. 10k,l).