Comparison of promoter methylation of limited number of genes (n = 5 genes) P15, CDH1, ER, MDR1 and RARB2 in context of NPM1, CEBPA, FLT3 and WT1 mutations between childhood and adult AML demonstrated age-related differences in frequency of mutations as well as in methylation patterns [15]. This evidence concerns the gene ABCB1 and acute myeloid leukemia.