MeanAPAF1 methylation was higher in advanced-stage MDS (RAEB-1/RAEB-2) group of patients (12 out of 15 cases(80%), x2=2.93) compared with early-stage MDS (RA/RCMD/5q- syndrome) group (11 out of 39 cases(28.2%), x2=0.97) (P<0.01).Methylation frequency of APAF1 gene in MDS subgroups is shown in Figure 2. The gene discussed is APAF1; the disease is myelodysplastic syndrome.