DNA methylation in AML at diagnosis and relapse. Methylation in normal peripheral blood controls is shown as box plots with bars indicating 5% to 95% confidence intervals. Methylation densities in individual patients with AML and their changes are shown in the second and third columns. PGRA, PGRB, CDH13, and OLIG2 genes were methylated above the cutoff at diagnosis in most patients and their methylation densities further increased at relapse. LINE-1 repetitive element showed a higher methylation in AML compared with normal peripheral blood controls and a slight decrease in methylation at relapse compared with diagnosis.