A vaccine for cancer may seem too good to be true, but the use of vaccines to treat cancer is being heavily investigated and is progressing rapidly, and a vaccine that can prevent 70 % of cervical cancer has already been approved. However, unlike conventional vaccines, most cancer vaccines will not prevent cancer but will be used to treat it, but they will still use the basic mechanism to fight tumor cells as a vaccine uses to fight viruses.

A vaccine fights infection by enabling the body’s natural immune system to better recognize the pathogen. Immune cells called T cells and B cells look for specific antigens, usually small pieces of cells or viruses that the immune system recognizes as foreign, and then reproduce themselves to better fight the antigens they have found. T cells identify and kill cells or viruses that contain the antigen, and B cells produce antibodies that attach to the antigen and kill the cell or virus by indirect means. Each T and B cell recognizes a different antigen, and when it finds its target, it makes many copies of itself. This way, the body targets the invasion by reproducing the cells that go after the specific substance that has already been identified as foreign. A vaccine just gives the immune system a head start in this very same process. A vaccine for smallpox contains smallpox viruses that are somehow disabled so that they cannot infect the vaccine recipient. When the viral particles enter the cell, the T cells and B cells that recognize the virus replicate themselves, so the immune system already has plenty of cells looking for smallpox viruses when the real viruses actually arrive. The viruses are then attacked immediately upon entrance into the body and never get the chance to start an infection. The vaccine triggers the natural immune response so that it is underway before the pathogen even enters the body. Vaccines have a big potential advantage over chemotherapy; while chemotherapy can kill tumor cells immediately, their effect on cancer as a disease may last only weeks or months. Vaccine-induced tumor regression, by contrast is more long-lasting.

The personalisation of treatment is not only the grail for cancer research, but remains the only hope of ensuring that increasingly expensive treatments are affordable to society. At present there is no form of cancer for which cancer vaccines are the standard therapy or any part of the standard therapy. But there is much exciting research and trials continue.

What are cancer vaccines?

New: Immune system protein could help develop cancer vaccine