ABL1 and acute lymphoblastic leukemia: In all three cohorts, highly methylated status corresponding to the bi-allelic methylation was most frequently observed in BCP-ALL with favourable karyotypes such as high-hyperdiploid and ETV6::RUNX1, whereas it was rarely observed in BCP-ALL with unfavourable karyotypes such as MLL rearrangement and BCR::ABL1 [17].