METTL1 and cancer: Besidesthe role of METTL1 as the 'writer' protein for mRNA internalm7G installation, METTL1 is well-known to mediate m7G methylation at position 46 of cytoplasmic tRNA, and thismethylation has been shown to link with cancer progression and tumorigenesis,69−71 requiring a quantitative method for monitoring tRNA m7G dynamics in pathological processes.