Human papillomavirus vaccines for cervical cancer.

Cervical cancer is one of the most common causes of cancer-related death in women. As a result of several recent advances in molecular biology, the association between human papillomavirus (HPV) infection and cervical cancer has been firmly established, and the oncogenic potential of certain HPV types has been clearly demonstrated. Several lines of evidence suggest the importance of the host's immune response, especially cellular immune response, in the pathogenesis of HPV-associated cervical lesions. These observations form a compelling rationale for the development of vaccine therapy to combat HPV infection. Both prophylactic and therapeutic HPV vaccine strategies are being developed. Prophylactic strategies currently under investigation focus on the induction of effective humoral immune responses against subsequent HPV infection. In this respect, impressive immunoprophylactic effects have been demonstrated in animals using papillomavirus-like particles (VLPs). VLPs are antigenic and protective, but are devoid of any viral DNA that may be carcinogenic to the host. For treatment of existing HPV infection, techniques to improve cellular immunity by enhancing viral antigen recognition are being studied. For this purpose, the oncogenic proteins E6 and E7 of HPV-16 and -18 are the focus of current clinical trials for cervical cancer patients. The development of successful HPV-specific vaccines may offer an attractive alternative to existing screening and treatment programs for cervical cancer.