Update on human papillomavirus vaccines for cervical cancer

Cervical cancer is a leading cause of cancer related mortality in women, particularly in developing countries. As a result of several recent advances in molecular biology, the causal 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. In recognition of the causal association of cervical cancer with a sexually transmitted viral infection, substantial interest has arisen to develop effective prophylactic and therapeutic vaccines. Prophylactic strategies currently under investigation focus on the induction of effective humoral immune responses that are potentially protective against subsequent HPV infection. Using recombinant techniques to express the L1 major capsid protein, papillomavirus-like particles (VLPs) have been synthesized in order to induce neutralizing antibody responses and impressive immunoprophylactic effects have been demonstrated in both animals and humans. For the 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 and cost-effective alternative to existing screening and treatment programs for cervical cancer.