What Are Cancer Vaccines?

Most people are familiar with vaccines as tools for preventing infectious diseases like polio and smallpox. In the world of cancer care, scientists are making strides in using vaccines in a new way: to prevent and treat cancer. 

Cancer vaccines are a type of immunotherapy that use tumor-specific proteins to help the immune system recognize and attack cancer cells. Some vaccines are used to prevent infections that can lead to cancer, while others are designed to treat cancer itself. 

At the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting, researchers shared encouraging results from multiple new cancer vaccine studies in melanoma, glioblastoma and head and neck cancer. Just last month, Moderna and Merck announced more promising results from a clinical trial of their personalized mRNA vaccine for melanoma, which succeeded in reducing the recurrence of melanoma when combined with the immunotherapy drug Keytruda. 

As research continues to accelerate the use of cancer vaccines, patients may wonder how these treatments work, whether they may be an option for them, and how researchers are using new technology to create more personalized cancer treatments. 

Prevention vs. treatment vaccines

There are two types of cancer vaccines: preventive vaccines and therapeutic vaccines. 

Preventive cancer vaccines protect against infections that can cause cancer later in life. About 15-20% of all cancers are linked to these viral infections. These work by exposing your body to a weakened form of a virus or bacteria to help your immune system recognize markers of the disease and build resistance to them.

There are two FDA approved cancer prevention vaccines: the human papillomavirus (HPV) vaccine and the hepatitis B (HepB) vaccine. “Currently, the HPV vaccine is recommended at ages 11–12, though it’s encouraged as early as age 9, to prevent HPV infections that can lead to cervical, anal, penile, vulvar, vaginal and head and neck cancers,” says Andria Reyes, MA, Health Education Manager at the Herbert Irving Comprehensive Cancer Center (HICCC). “The HepB vaccine is recommended at infancy to prevent hepatitis B infection, a major cause of liver cancer. These vaccines are two of the best, and most accessible, tools we have for preventing cancer.” 

HPV vaccination, in particular, has brought cervical cancer elimination within reach, with some countries already approaching the World Health Organization’s criteria for complete elimination of the disease. 

Cancer vaccines can also be used to treat cancer and are called therapeutic cancer vaccines. Instead of preventing an infection, these vaccines use information from a patient’s tumor to help the immune system recognize and attack cancer cells. 

Therapeutic cancer vaccines

Cancer can be difficult for the immune system to detect because cancer cells develop from the body’s own healthy cells. Therapeutic cancer vaccines help teach the immune system to recognize the cancer cells and attack them. 

Cancer vaccines target antigens, or proteins found on cancer cells. Some target neoantigens—new proteins created by genetic changes found only in cancer cells. Because neoantigens are unique to an individual’s tumor, they may provide highly specific targets for treatment.  

Three therapeutic cancer vaccines are already approved for specific cancers: Bacillus Calmette-Guérin (BCG) has been used for decades to treat some bladder cancers. Sipuleucel-T (Provenge) is approved for certain advanced prostate cancers. Talimogene laherparepvec (T-VEC or Imlygic), an engineered virus, is approved to treat some melanomas and can stimulate an immune response against cancer. 

When are cancer vaccines used?

Cancer vaccines are not right for every patient or every type of cancer. Researchers are still learning which cancers are most likely to respond and how cancer vaccines work best with other treatments. 

A therapeutic cancer vaccine may be used alongside other cancer treatments. Larger or more advanced tumors can be difficult to treat with a vaccine alone, which is one reason researchers are studying vaccines in combination with immunotherapies and other treatments. 

"Where these vaccines appear to work best is after the tumor has been removed, rather than using them to treat a large tumor," says Benjamin Izar, MD, PhD, physician-scientist at the HICCC with a focus on the treatment of advanced melanoma. "Together with immunotherapy, the vaccine can train the immune system to recognize the cancer and go after any cells that might still be there. The hope is that this keeps the cancer from coming back or spreading."

Cancer vaccine research at Columbia

At Columbia, researchers are exploring innovative ways to help the immune system better recognize and fight cancer. 

In the lab of Santiago Correa, PhD, researchers are engineering new ways to activate the immune system against cancer. His team develops materials and technologies that could help cancer vaccines deliver their signals more effectively and trigger a stronger immune response. 

Nicholas Arpaia, PhD, and Tal Danino, PhD, are studying engineered bacteria that can deliver cancer-fighting signals directly to tumors. The bacteria act as delivery vehicles, concentrating these signals where the cancer cells are. The approach could eventually be tailored to an individual patient’s cancer, including tumors that have spread.