EP300 and breast carcinoma: Our results converge with and extend previous data reporting a connection between p300/CBP and induction of cellular senescence: indeed, p300 was found to be a primary driver of the senescent phenotype in normal cells [41, 42] and p300/CBP inhibition by either C646 or A-485 HAT inhibitors led to senescence in melanoma and breast cancer cells [27, 32, 43].