Papillomaviruses--to vaccination and beyond.

High risk human papillomavirus (HPV) types 16 and 18 DNAs were initially identified in 1983–1984. Subsequently the DNA of several other high risk HPV types has been identified. HPV 16 is present in more than 50% of cervical cancer biopsies, and HPV 18 is close to 20%. Some geographic variations exist in the prevalence of HPV high risk types: e.g. HPV 45 is more frequently observed in equatorial Africa, whereas types 58 and 52 have been more often found in East Asia. Molecular as well as epidemiological studies demonstrate that high risk HPV are indeed the causative agents for cervical cancer, they are also involved in other anogenital cancers, and in 25–30% of oropharyngeal carcinomas. Some of the mechanistic aspects are discussed in this review.