RB1 and hepatocellular carcinoma: Our initial efforts to study epigenetic instability of imprinted genes in HCC have revealed frequent DNA methylation aberrations resulting in biallelic expression and allele switching at the DLK1-MEG3 imprinting cluster [14] and identified the well-known tumour suppressor gene RB1 as a new target for imprint dysregulation in human HCC [15].