H19 and neoplasm: Although gain of methylation events at the H19 ICR were found in both subgroups, the concurrent loss of methylation events at the KCNQ1OT1 ICR reflecting 11p15 UPD were more prevalent in Subgroup B. Thirty-three percent and 40% of Subgroup B tumours had a gain of methylation at H19 or DNA methylation changes at both ICRs, respectively, compared to 32% and 9% of Subgroup A tumours.