H19 and hemoglobin measurement: To determine whether the alterations of IGF2 and H19 loci identified in WT are also found in HB, we examined the LOI and LOH status of IGF2 using combined bisulphite restriction assay (COBRA) of the CTCF6 region that can determine the methylation status of H19 DMR more efficiently than the method using methylation-specific restriction enzymes and Southern blot in 54 HB tumours.