Vaccines against human papillomavirus.

Human papillomavirus has been identified as an etiological factor for cervical cancer, anogenital cancers and a subset of head and neck cancers. These important observations suggest that HPV vaccines have potential in the prevention and treatment of cervical cancer and other HPV-associated malignancies. The HPV genome encodes two HPV late genes, L1 and L2, which form the viral capsid. Early viral proteins support viral genome replication, two of which (E6 and E7) are important for HPV associated malignant transformation. Prophylactic HPV vaccines prevent infection by inducing neutralizing antibodies against HPV capsid proteins L1 and L2. However, because HPV-infected basal keratinocytes and HPV-transformed cells generally do not express L1 or L2, therapeutic HPV vaccines aim to treat established HPV infections and HPV-associated malignancies by targeting non-structural early viral antigens of HPV such as E6 and E7. Results from preclinical HPV vaccine studies have led to several HPV vaccine clinical trials. If these prophylactic and therapeutic HPV vaccines prove as successful in patients as they have in animal models, vaccination may provide for control and eventually eradication of oncogenic HPV infection and HPV-related cancers.