METTL1 and head and neck squamous cell carcinoma: The m7G regulatory factors methyltransferase 1 (METTL1) and WD Repeat Domain 4 (WDR4) participate in the regulation of various cancer types, including HNSCC, liver cancer, bladder cancer, and lung cancer, by changing the m7G modification levels of miRNAs and tRNAs 18,19.