Long non-coding RNA (lncRNA) covers most of the messages from the human DNA without protein-coding potential, which is a wide range of complicated molecules that consist of more than 90% of the whole genomic and present in different forms in the course of pathophysiology of cancers. In 2003, lncRNA MEG3 was firstly discovered as a potential tumor-inhibiting factor of pituitary adenomas. Later on, the roles and mechanisms in the regulation of gene expression, imprinting, transcription, and post-translation of MEG3 in meningioma, hepatocellular cancer, lung cancer, neuroendocrine tumor, prostate cancer and other kinds of tumors were further clarified, indicated that the expression of MEG3 was down-regulated or deficient in a wide range of tumors while the expression up-regulation of MEG was greatly correlated with tumor inhibition. The function of MEG3 and its research progress in tumorigenesis were summarized in this paper. [ABSTRACT FROM AUTHOR]