The Investigators randomized AML patients to receive G-CSF 100 mg/m2 from day 0 to 5 and decitabine 5 mg/m2 on days 1-5 in 6 weeks cycle, up to a maximum of 6 cycles (G-DEC group) or observation only in the control group. The gene discussed is CSF3; the disease is acute myeloid leukemia.