MS-275–induced increase in protein acetylation correlates with increase in p21 expression and caspase-3 activation in BMMCs as determined by flow cytometry. (A) Protein hyperacetylation versus CD34 expression before and after MS-275 (day 8, patient 38, DL 5). Note that in this patient all of the CD34⁺ cells became hyperacetylated but not all of the CD34⁻ cells. (B) Protein hyperacetylation versus p21 expression in BMMCs before and after MS-275 (day 15, patient 33, DL 5). (C) Comparison in individual patients of the effect of MS-275 on protein hyperacetylation and p21 expression in BMMCs. (D) Protein hyperacetylation versus caspase-3–activated form expression in BMMCs before and after MS-275 (day 8, patient 20, DL 4). (E) Comparison in individual patients of the effect of MS-275 on protein hyperacetylation and caspase-3 activation in BMMCs. Correlations were performed in at least 7000 individual cells by multiparameter flow cytometry using a FACSCalibur flow cytometer (Becton Dickinson).