METTL14 and cancer: M6A methyltransferases (e.g., methyltransferase like 3-METTL3, METTL14, and METTL16), m6A demethyltransferases [e.g., fat mass and obesity-associated protein (FTO) and AlkB homolog 5 (ALKBH5)], and adaptive factors [e.g., Wilm’s tumor 1-related protein (WTAP), RNA binding motif protein 15 (RBM15), YTH domain (YTHs), and heterogeneous nuclear ribonucleoproteins (HNRNPs)] are involved in the progression of malignant tumors by recognizing m6A upon the reading, erasing, or writing of binding RNA in different tumors [20].