CDKN2A and head and neck squamous cell carcinoma: Although several papers have shown the prognostic significance of p16INK4a even in the absence of HPV positivity there are contradictory studies showing significant poor survival rates for HPV−/p16INK4a+ HNSCC patients compared to HPV+/p16INK4a+ HNSCC patients [68,72,73,74,75].