RNA N 6 -methyladenosine modification in cancers: current status and perspectives.

N6 -methyladenosine (m6 A), the most abundant internal modification in eukaryotic messenger RNAs (mRNAs), has been shown to play critical roles in various normal bioprocesses such as tissue development, stem cell self-renewal and differentiation, heat shock or DNA damage response, and maternal-to-zygotic transition. The m6 A modification is deposited by the m6 A methyltransferase complex (MTC; i.e., writer) composed of METTL3, METTL14 and WTAP, and probably also VIRMA and RBM15, and can be removed by m6 A demethylases (i.e., erasers) such as FTO and ALKBH5. The fates of m6 A-modified mRNAs rely on the functions of distinct proteins that recognize them (i.e., readers), which may affect the stability, splicing, and/or translation of target mRNAs. Given the functional importance of the m6 A modification machinery in normal bioprocesses, it is not surprising that evidence is emerging that dysregulation of m6 A modification and the associated proteins also contributes to the initiation, progression, and drug response of cancers. In this review, we focus on recent advances in the study of biological functions and the underlying molecular mechanisms of dysregulated m6 A modification and the associated machinery in the pathogenesis and drug response of various types of cancers. In addition, we also discuss possible therapeutic interventions against the dysregulated m6 A machinery to treat cancers.