Natural history and epidemiology of HPV infection and cervical cancer.

Cervical cancer is the most common cancer affecting women in developing countries. It has been estimated to have been responsible for almost 260 000 deaths annually, of which about 80% occurred in developing countries. Persistent infection by certain oncogenic HPV types is firmly established as the necessary cause of most premalignant and malignant epithelial lesions of the cervix and of a variable fraction of neoplastic lesions of the vulva, vagina, anus, penis, and oropharynx. There are more than 100 known HPV genotypes, at least 15 of which can cause cancer of the cervix and other sites. HPV 16 and 18, the two most common oncogenic types, cause approximately 70% of all cervical cancers worldwide. HPV, especially genotypes 6 and 11, can also cause genital warts. HPV is highly transmissible and it is now considered the most common sexually transmitted infection in most populations. Although most women infected with the virus become negative within 2 years, women with persistent high-risk HPV infections are at greatest risk for developing cervical cancer. Since the identification of HPV as the necessary cause of cervical cancer, HPV-based technology has become the centre of novel primary and secondary cervical cancer prevention strategies by the introduction of HPV testing in screening and of HPV vaccines in preadolescent girls and young women. If implemented widely and wisely the deployment of these protocols has the potential to complete Papanicolaou's goal of cervical cancer eradication by extending the benefits of prevention to the developing populations of the world.