Cancer vaccines have seemed like medicine's Holy Grail: much discussed, much sought after, but always elusive.
After decades of failed attempts, some vaccines are now advancing through clinical trials. A new vaccine against human papillomavirus—the common sexually transmitted virus that can cause cervical cancer—is being billed as a cancer vaccine both by its manufacturer and the U.S. Food and Drug Administration, which approved the vaccine in June. (The FDA also classifies the hepatitis B vaccine, which was approved in 1981, as a cancer vaccine because hepatitis B is associated with liver cancer.)
Although other vaccines are being investigated to prevent cancer commonly caused by infectious agents, most vaccines under