However, discordant patterns, including HPV DNA-positive but p16 IHC-negative (indicated as HPV DNA+/p16 IHC−) and HPV DNA-negative but p16 IHC-positive (indicated as HPV DNA−/p16 IHC+) cases, have also been observed in HNSCC [14,15]. Here, CDKN2A is linked to head and neck squamous cell carcinoma.