A virus-based vaccine may prevent cervical cancer

High-risk human papillomaviruses (HPVs) are now recognized as the etiologic agents of invasive cervical cancer, a major cancer in women. A single HPV type (type 16) is responsible for about 50% of the cancers. The major capsid protein of papillomaviruses, L1, when expressed by recombinant DNA technology, has the intrinsic ability to assemble into virus-like particles (VLPs). In a recent study, a vaccine based on HPV 16 VLPs was tested in a placebo-controlled proof-of-principle trial in young women in the United States. The vaccine was found to prevent 100% of incident persistent HPV 16 infections and HPV 16-associated cervical intraepithelial neoplasia. These results offer promise that cervical cancer will be preventable by an HPV-based vaccine. Studies planned or in progress are examining the efficacy of the vaccine in men, in HIV-infected individuals, and in other parts of the world. Attempts are being made to prepare vaccines that can be administered more easily to large populations.