METTL1 and cancer: The m7G “writer” METTL1 suppresses the expression of S100A4 through m7G modification and upregulates miR-149-3p via a p53-dependent mechanism, thereby reducing the chemoresistance of CRC cells to cisplatin.548 Furthermore, the silencing of METTL1, which also methylates tRNAs at the variable loop of several tRNAs, has been shown to increase the sensitivity of cancer cells to 5-FU by increasing cell death555,556 (Fig. 5).