Novel insights into the m⁶A-RNA methyltransferase METTL3 in cancer

N6-methyladenosine (m⁶A) is a prevalent internal RNA modification in higher eukaryotic cells. As the pivotal m⁶A regulator, RNA methyltransferase-like 3 (METTL3) is responsible for methyl group transfer in the progression of m⁶A modification. This epigenetic regulation contributes to the structure and functional regulation of RNA and further promotes tumorigenesis and tumor progression. Accumulating evidence has illustrated the pivotal roles of METTL3 in a variety of human cancers. Here, we systemically summarize the interaction between METTL3 and RNAs, and illustrate the multiple functions of METTL3 in human cancer. METLL3 is aberrantly expressed in a variety of tumors. Elevation of METTL3 is usually associated with rapid progression and poor prognosis of tumors. On the other hand, METTL3 may also function as a tumor suppressor in several cancers. Based on the tumor-promoting effect of METTL3, the possibility of applying METTL3 inhibitors is further discussed, which is expected to provide novel insights into antitumor therapy.