CDKN2A and head and neck squamous cell carcinoma: Using the same histological criteria as Klaes et al (14), Hoffmann et al reported that 81.2% of HPV DNA-positive HNSCC patients were also p16INK4a positive, compared with only 48.2% of HPV DNA-negative cases, including 3 cases with strong and diffuse p16INK4a staining.