EDNRB hypermethylation in ctDNA, on the other hand, significantly associated with HNSCC when comparing an aggregate group of HPV-positive and HPV-negative HNSCC patients with healthy controls, but it is detectable in only a minority of HNSCC patients, limiting its value as a diagnostic biomarker [72]. Here, EDNRB is linked to head and neck squamous cell carcinoma.