In a parallel set of experiments, we omitted Q-VD-OPh and examined the ability of CPX-351 to kill AML cell lines by assessing DNA cleavage (Fig. 2a–c), phosphatidylserine externalization (Fig. 2d–f), PARP1 cleavage (Fig. 2g) and nuclear fragmentation (Supplementary Fig. S2), four separate hallmarks of apoptosis. The gene discussed is PARP1; the disease is acute myeloid leukemia.