Discovery of AML1-ETO abrogation signature. (A) Kasumi-1 immunoblot with AML1 antibody demonstrates loss of AML1-ETO protein expression 96 hours after transient transfection with siRNA by Amaxa. (B) Real-time PCR with AML1-ETO–specific primers reveals loss of AML1-ETO RNA at 24 hours. (C) Transcriptional profiling of Kasumi-1 cells on Affymetrix U133A microarrays reveals AML1-ETO abrogation signature in Kasumi-1 cells with both lipid and Amaxa transfection. Dark red indicates high gene expression and dark blue indicates low gene expression. The corresponding gene expression in AML1-ETO–inducible U937 cells is indicated. (D) Gene set enrichment analysis demonstrates enrichment of the AML1-ETO abrogation signature in primary AML patient cells expressing t(8;21) versus other molecular subtypes of AML.