How Do Cancer Vaccines Work?

Cancer vaccines work much the same way as a vaccine you might get for flu or COVID – by stimulating the immune system to respond to a specific target or antigen. In the case of cancer vaccines, this could be a virus linked to cancer (like HPV or hepatitis B) or abnormal proteins found on the surface of cancer cells.

Once the immune system learns to recognize these targets, it can launch a stronger, more focused response—either to stop cancer from forming or to fight it after it has appeared.

Preventive (Prophylactic) Cancer Vaccines

Some cancers can be caused by viruses infecting normal cells. For example, the virus HPV can infect cells, insert new genetic material into the cell’s DNA and cause the cell to grow uncontrollably. This can lead to the development of several cancer types, most notably cervical and throat cancers.

Preventive vaccines protect against infections, such as HPV, that are known to cause cancer. These vaccines train the immune system to recognize and destroy viruses before they can infect cells and lead to cancer over time.

Therapeutic (Treatment) Cancer Vaccines

Therapeutic vaccines are designed to treat existing cancers by helping the immune system better recognize and attack cancer cells. These vaccines introduce the immune system to proteins or molecules (known as antigens) that are found mostly on cancer cells. This helps immune cells—especially T cells—spot and destroy those cancer cells more effectively. Therapeutic cancer vaccines are an area of new research but one vaccine, called Provenge (sipuleucel-T), has been approved for advanced prostate cancer.

What’s Next for Cancer Vaccines?

Cancer vaccines are an exciting and growing field of research. Scientists are exploring how to:

• Combine vaccines with other immunotherapies
  Using vaccines alongside checkpoint inhibitors or CAR T cell therapy to boost the immune response.
• Personalize cancer vaccines
  Creating vaccines tailored to an individual’s unique tumor characteristics, using genetic information or tumor samples.
• Improving immune responses in “cold” tumors
  Developing strategies to help vaccines work better in tumors that usually don’t trigger much of an immune reaction.
• Developing “universal” cancer vaccines
  Researchers are exploring vaccines that could target common features found in many types of cancer, not just one. These universal vaccines aim to train the immune system to recognize patterns or proteins shared across multiple cancers—potentially offering broad protection or treatment with a single shot.

Universal cancer vaccines are still an area of early research, but represent a bold goal: a single vaccine that could help prevent or treat multiple cancers by tapping into the shared biology of tumor cells.