TLR1/TLR2 activation leads to differentiation of AML cells. (A) TLR1 expression on human MA9 leukemia cells. Histogram showing MA9 cells stained for TLR1 (red) and isotype control (purple line) using flow cytometry. (B-D) MA9 cells were treated with or without (control) Pam3CSK4 for 3 days. (B) Percentage of CD14⁺ cells measured by flow cytometry (n = 3). (C) May-Grünwald-Giemsa–stained cytospin slides (40× magnification). (D) Cell cycle status of MA9 cells from 1 representative experiment of 3. (E-F) In MA9 cells treated with Pam3CSK4 for 24 h, GSEA identified an enriched (E) myeloid cell differentiation signature and (F) a LSCs down signature; that is, a signature of genes downregulated in LSCs (AML cell populations with high versus low LSCs frequency). Mean values and SDs are shown. **P < .01; ****P < .0001.FDR, false discovery rate; NES, normalized enrichment score.