The downregulation of the MEG3 expression (the imprinted gene that encodes a specific lncRNA) in some pituitary tumor subtypes, mainly in clinically nonfunctioning adenomas, was confirmed by several studies, and overall hypermethylation in the important regulatory regions of the gene is an additional mechanism that contributes to the specific loss of expression [107,108,109,110]. This evidence concerns the gene MEG3 and pituitary tumor.