The methylation frequency of the CHFR gene in HPV-negative tumors is in concordance with previous data reported for HNSCC, although the results in HPV-positive OPSCCs and cervical SCC are in contrast to a previous publication showing CHFR promoter methylation in HPV-positive cervix carcinomas 27, 38. Here, CHFR is linked to head and neck squamous cell carcinoma.