Three-drug combination treatment exerts synergistic proapoptotic effects in AML blasts with NRAS mutations. Mononuclear cells obtained from peripheral blood and bone marrow samples of AML patients with (A) or without (B) NRAS mutations were exposed to AZD8055, selumetinib, and/or ABT737 at the indicated concentrations (in μmol/L) for 24 to 72 hours. C, The specific apoptosis was determined in triplicate samples based on the triple-drug treatment data shown in Fig. 5A and 5B, and shown as a comparison between bulk and CD33+/34+ fractions of the NRAS mutated and NRAS-wild samples. ** P < 0.01. D, AML patient sample (case 7) was treated with indicated concentration (μmol/L) of inhibitors for 24 hours, and correlative protein expression was determined by immunoblotting.