(gene) inhibitor vemurafenib. The following table, summarizing information from another recent review shows an example of the antigen used in the vaccine tested in Phase 1/2 clinical trials for each of 10 different cancers: Approved oncovaccines Oncophage was approved in Russia in 2008 for kidney cancer. It is marketed by Antigenics Inc. Sipuleucel-T, Provenge, was approved by the FDA in April 2010 for metastatic hormone-refractory prostate cancer. It is marketed by Dendreon Corp. Bacillus Calmette-Guérin (BCG) was approved by the FDA in 1990 as a vaccine for early-stage bladder cancer. BCG can be administered intravesically (directly into the bladder) or as an adjuvant in other cancer vaccines. Abandoned research CancerVax (Canvaxin), Genitope Corp (MyVax personalized immunotherapy), and FavId FavId (Favrille Inc) are examples of cancer vaccine projects that have been terminated, due to poor phase III and IV results. Desirable characteristics Cancer vaccines seek to target a tumor-specific antigen as distinct from self-proteins. Selection of the appropriate adjuvant to activate antigen-presenting cells to stimulate immune responses, is required. Bacillus Calmette-Guérin, an aluminum-based salt, and a squalene-oil-water emulsion are approved for clinical use. An effective vaccine should also stimulate long term immune memory to prevent tumor recurrence. Some scientists claim both the innate and adaptive immune systems must be activated to achieve total tumor elimination. Antigen candidates Tumor antigens have been divided into two categories: shared tumor antigens; and unique tumor antigens. Shared antigens are expressed by many tumors. Unique tumor antigens result from mutations induced through physical or chemical carcinogens; they are therefore expressed only by individual tumors. In one approach, vaccines contain whole tumor cells, though these vaccines have been less effective in eliciting immune responses in spontaneous cancer models. Defined tumor antigens decrease the risk of autoimmunity, but because the immune response is directed to a single epitope, tumors can evade destruction through antigen loss variance. A process called "epitope spreading" or "provoked immunity" may mitigate this weakness, as sometimes an immune response to a single antigen can lead to immunity against other antigens on the same tumor. For example, since Hsp70 plays an important role in the presentation of antigens of destroyed cells including cancer cells, this protein may be used as an effective adjuvant in the development of antitumor vaccines. Hypothesized problems A vaccine against a particular virus is relatively easy to create. The virus is foreign to the body, and therefore expresses antigens that the