Suppressing CBP/p300 activity via A-485, a selective inhibitor of the CBP/p300 acetyltransferase domain, in cancer cells addicted to these transcription factors results in viability defects (Lasko et al, 2017; Waddell et al, 2021; Welti et al, 2021; Zhang et al, 2020b). Here, EP300 is linked to cancer.