However, our findings presented here clearly demonstrate that E1ACR1 (p300-binding; Δ48–60) was essential for enhancement of drug-induced apoptosis but not the p400-binding region (Δ26–35) and E1ACR2 (pRb-binding; Δ122–129) in our prostate cancer models. The gene discussed is EP300; the disease is prostate carcinoma.