While our studies focussed on the use of ActD as it is a drug commonly used for the treatment of a variety of cancers, we found that Nutlin-3, another p53 activator which has been successfully used in cyclotherapy, could protect HCT116+/+p53 but not HCT116−/−p53 cells from MLN4924-induced toxicity with similar efficiency to ActD (supplementary information, Fig. S1). The gene discussed is TP53; the disease is cancer.