Numerous chemotherapy agents rely on an intact p53 pathway for optimal activity,14 and p53 dependency for BET bromodomain inhibitor-mediated apoptosis may be cell context dependent.15, 16 We therefore examined I-BET762 sensitivity of Eμ-myc/p53−/− and Eμ-myc/p19arf−/− lymphomas. The gene discussed is TP53; the disease is lymphoma.