DIO3 and cancer: Many human tumours show hypermethylation at the IG-DMR of the DLK1-DIO3 imprinted locus and consequently express very low levels of MEG3 (the human homologue of mouse Gtl2), suggesting a role for MEG3 in the onset and progression of cancer (Astuti et al., 2005, Braconi et al., 2011, Tian et al., 2015, Wang et al., 2017, Zhang et al., 2017, Zhang et al., 2003).