Preliminary results from the analysis of five HPV-positive tumors from patients participating in this window of opportunity study showed that after 5 or 7 days of treatment, azacytidine decreased the expression of HPV genes by approximately 2–5-fold, stabilized and increased the expression of p53, and induced the activation of caspase 3 and apoptosis in HPV-positive HNSCC tumors. The gene discussed is TP53; the disease is head and neck squamous cell carcinoma.