Studies also reported that deletion of the MEG3 locus usually led to more aggressive cancers and MEG3 expression level correlated with tumor grade and prognosis in meningiomas [25], colorectal cancer (CRC) [54], NFPA [45], gastric cancer (GC) and cervical cancer [23, 49, 50]. This evidence concerns the gene MEG3 and non-functioning pituitary adenoma.