As shown in Table 2, GO induced γH2AX within 6 hours of drug exposure in all primary AML specimens, with the extent of γH2AX induction being highly correlated to CD33 expression levels (r = 0.831 [0.492–0.951], P = 0.0008; Figure 2), indicating that CD33 expression is a limiting factor for the intracellular accumulation of the calicheamicin-γ1 derivative. The gene discussed is CD33; the disease is acute myeloid leukemia.