Interestingly, the intrinsically cetuximab‐resistant cell lines 93‐VU‐147T and SQD9 demonstrated huge levels of, respectively, HER2 (ΔMFI = 1792.3 ± 125.6) and HER3 expression (ΔMFI = 4229.7 ± 1068.2) compared to the other HNSCC cell lines. This evidence concerns the gene ERBB3 and head and neck squamous cell carcinoma.