Abstract
Transmission of papillomaviruses typically occurs by direct skin-to-skin contact, and in the anogenital tract mostly by sexual intercourse. Infections often remain without symptoms and are in most instances transient depending on the human papillomavirus (HPV) type. Persistent infections with the high-risk (HR) types are the precondition for the development of a high-grade lesion and subsequently cancer, whereat the ‘transforming potential’ of HPV16, 18 and 45 is clearly distinct from the 10 other HR types. Almost all of the worldwide occurring cases of cervical cancer are related to HPV, yet in comparison to the incidence of infection, it occurs rarely and late after exposure. Other carcinomas of the anogenital tract and of the head and neck are also related to HPV (mostly HPV16), yet the fraction of positive cases is smaller.