Importantly, when HNSCC cell lysates (HN4, SCC9, and FaDu) treated with recombinant peptide-N-glycosidase F (PNGase F) glycosidase, which removes the entire N-glycan structure in vitro, glycosylated EREG (30 kD) was degraded into unglycosylated form (20 kD) (Fig. 3e). This evidence concerns the gene EREG and head and neck squamous cell carcinoma.