CDKN2A and neoplasm: In oropharyngeal SCCs, 2–20% of p16 positive cases are high risk HPV negative [21, 33] and in the recent meta-analysis, p16+/HPV- tumours are shown to have worse 5-year overall survival and 5-year disease-free survival than p16+/HPV+ tumours (81.1% vs. 54.7%; 84.3% vs. 67.9%) [27].