HPV-positive tumours show distinct molecular profiles as compared to HPV-negative tumours, with less frequent mutations in TP53 (4%, 10/236 vs. 68%, 1177/1733, p < 0.001), HRAS (2%, 4/236 vs. 7%, 110/1683, p < 0.01), CASP8 (1%, 1/134 vs. 14%, 117/838, p < 0.001) and CDKN2A (0%, 0/236 vs. 20%, 315/1585, p < 0.001), and an enrichment of PIK3CA mutations (29%, 68/236 vs. 14%, 234/1673, p < 0.001). The gene discussed is CDKN2A; the disease is neoplasm.