Effect of 5azaD/TSA treatment on cell cycle progression. After 5 days of initial culture, CD34⁺ cells were reisolated from culture containing 5azaD/TSA treatment or cytokines alone. Reisolated CD34⁺ cells were pulse-labeled with BrdU and then cultured without BrdU or additional 5azaD/TSA treatment for an additional 48 hours. The harvested cells were stained with FITC-anti-BrdU mAb and PI, and BrdU⁺ S phase cells quantitated every 6 to 12 hours by flow cytometry. The results show the percentage of BrdU⁺ cells in the S phase at indicated time intervals.