Epidemiology of genital papillomaviruses and cervical cancer.

Cervical cancer is an extremely common disease. Its natural history has been well described, and individual risk factors have been defined. It is clear from the epidemiologic evidence that cervical cancer has a multifactorial etiology involving infection with sexually transmitted agents such as genital papillomaviruses and cofactors such as pregnancy, smoking, use of hormonal contraceptives, and diet. The evidence implicating papillomavirus as an etiologic agent of cervical cancer has come from a variety of observational laboratory studies. Genital papillomaviruses induce dysplastic lesions. Most invasive cervical cancers contain papillomavirus DNA, as do cell lines derived from cervical cancers. Viral DNA, appears to be integrated into cellular DNA, and integration involves highly conserved, transcriptionally active regions of the viral DNA.