CDKN2A and oropharynx squamous cell carcinoma: Here, to evaluate the accuracy of p16INK4a expression for determining HPV infection and the prognostic value of HPV infection and p16INK4a expression for HNSCC survival, especially oropharyngeal squamous cell carcinoma (OPSCC) survival, 150 fresh-frozen HNSCC samples were analyzed for HPV DNA, E6/E7 mRNA and p16INK4a expression by polymerase chain reaction and immunohistochemistry.