Confirming DNA damage indicated by immunoblots (Figure 1A), 5-azaC treatment of HPV+ HNSCC cells increased ɣH2AX foci, but RAD51 was not induced and poorly colocalized with ɣH2AX in HPV+ UMSCC47 (Figure 1B). This evidence concerns the gene H2AX and head and neck squamous cell carcinoma.