Exosomal content analysis has revealed differences between HPV+ and HPV− HNSCC: one study found that HPV+ cell-derived exosomes contained viral oncogene transcripts and a distinct protein profile (e.g., presence of p16, E6/E7, and immunosuppressive proteins like PTPN11) [39,40]. The gene discussed is CDKN2A; the disease is head and neck squamous cell carcinoma.