Of these 14 genes, the majority of writers (NOP2, NSUN2, NSUN3, NSUN4, NSUN5, NSUN6, DNMT3A, DNMT3B, and DNMT1) were more substantially upregulated in the HNSCC samples compared with normal tissues, with the exception of NSUN7, which showed an opposite expression trend with the other 9 m5C writers (p < 0.05). Here, NSUN4 is linked to head and neck squamous cell carcinoma.