RB1 and head and neck squamous cell carcinoma: It has been reported that E6 and E7 viral proteins from HPV-16 cause the functional loss of TP53 and Rb tumor suppressors in HPV-positive HNSCC, and that HPV-positive HNSCC often lacks mutation in TP53, which would explain the far more favorable outcome of HPV-positive HNSCC [3, 4].