In most human cancer cell lines and certain primary tumors, such as pituitary adenoma, MEG3 is downregulated via hypermethylation of the maternal allele, but its ectopic expression reduces tumor progression; thus, MEG3 acts as a tumor suppressor (Cheunsuchon et al., 2011, Zhou et al., 2012). The gene discussed is MEG3; the disease is pituitary gland adenoma.