Objective  To determine the effect of Hes1 on bone marrow CD34⁺ cells in acute myeloid leukemia (AML).

  Methods  Bone marrow mononuclear cells were isolated by using Ficoll. Then, the proportion and cell cycle of CD34⁺ cells were analyzed by using fluorescence-activated cell sorting (FACS). CD34⁺ cells were cultured in vitro for colony-forming cells (CFC). The expression of Hes1 in CD34⁺ cells was evaluated by using real-time polymerase chain reaction. After upregulating the expression of Hes1 in CD34⁺ cells, the cell cycle was analyzed through FACS, and the colony formation of CD34⁺Hes1⁺ cells was analyzed by CFC.

  Results  The ratio of CD34⁺ cells in the bone marrow was lower in the AML group than in the control group. In addition, more CD34⁺ cells underwent quiescence in the AML group than in the control group. In vitro assay showed that the colony formation of CD34⁺ cells was lower in the AML group than in the control group. The expression of Hes1 was higher in the CD34⁺ cells from the AML patients than that in the CD34⁺ cells from normal donors. After Hes1 transduction, more CD34⁺ cells underwent quiescence and showed weak proliferation.

  Conclusion  The proportion of CD34⁺ cells in the bone marrow was lower in AML patients than in normal donors. A large proportion of CD34⁺ cells underwent quiescence, which was related to Hes1, in AML patients.