DOT1L inhibitor treatment selectively inhibits in vitro growth and induces terminal differentiation of primary patient samples with DNMT3A mutations. (A) Relative colony-forming units (CFU) of normal cord blood CD34⁺ cells and primary AML samples wild-type for both DNMT3A and MLL (left), primary AML samples with MLL anomalies (middle), and primary AML samples with DNMT3A mutations (right). *Non-R882 DNMT3A mutation treated with DMSO vehicle control or 3 μM EPZ004777. Assays performed in triplicate; error bars represent standard error of the mean. (B) Average change in CFC of primary patient samples treated with 3 μM EPZ004777 compared with DMSO vehicle–treated control. Error bars represent standard error of the mean. (C) Flow cytometry analysis of CD14 expression of primary AML cells with DNMT3A mutation isolated from plates after treatment with DMSO vehicle control or 3 μM EPZ004777. P value was determined using unpaired 2-way Student t test. *P < .05. ns, not statistically significant.