Beta-HPVs (types 5, 8, 38) likely act as co-carcinogens in sun-exposed skin by E6/E7-mediated interference with p53 and Rb, especially early in tumorigenesis and in immunosuppressed or genetically predisposed hosts (e.g., epidermodysplasia verruciformis) [38,39]. Here, RB1 is linked to epidermodysplasia verruciformis.