May 13, 2025
What are Cancer Vaccines, and How Do They Work?
Most people know that vaccines are available to prevent or reduce the risk of some infections and diseases. Did you know that vaccines are also available for certain types of cancer? Not only are there some vaccines to prevent cancer, but they can also be used therapeutically to treat cancer once it has been diagnosed.
How Cancer Vaccines Are Designed to Work
Vaccines generally work by introducing weakened or mutated disease-specific cells into the body, allowing the immune system to recognize these foreign invaders or abnormal cells through specific markers known as "antigens." When the immune system identifies these antigens, it responds to the threat.
Developing cancer vaccines, however, isn't as straightforward. Cancer cells turn off the immune system’s ability to identify foreign invaders. They look like normal, healthy cells, making it hard for the immune system to tell the difference. Cancer tumors are also unique due to having distinct antigens. A more sophisticated approach is needed to create effective therapeutic vaccines.
Preventive Cancer Vaccines
Preventative vaccines protect the body against foreign invaders like bacteria and viruses. Currently, two approved vaccines help prevent cancer by protecting against certain viral infections associated with the disease:
The HPV vaccine aims to prevent infection from the human papillomavirus. HPV is so common that nearly all sexually active individuals will be infected with it at some point during their lifetime. Chronic HPV infection can lead to several types of cancer, including cervical cancer, head and neck cancer, anal cancer, penile cancer, vaginal cancer, and vulvar cancer. The HPV vaccine can help reduce the risk of developing these cancers.
The hepatitis B vaccine protects against the hepatitis B virus (HBV), which can lead to liver disease. The severity of HBV can vary among individuals, and the longer someone remains infected with the virus, the greater the risk of developing liver cancer.
Therapeutic Cancer Vaccines
Cancer vaccines are used to treat people who have already received a cancer diagnosis. These vaccines differ from preventative vaccines in that they help your immune system learn to recognize and fight damaged or abnormal cells, including cancer cells.
Therapeutic cancer vaccines work in several different ways, such as stopping tumors from growing or spreading, eliminating leftover cancer cells after treatments like surgery or radiation, and preventing cancer recurrence. They do this by introducing your immune system to antigens linked to a particular type of cancer.
Cancer treatment vaccines can be created:
From your tumor cells. These vaccines are tailored to trigger an immune response against features unique to your cancer.
From tumor-associated antigens. These antigens are found on the cancer cells of many patients with a specific type of cancer. Vaccines from these antigens can generate an immune response in patients whose cancer produces that antigen. Currently, this is only an experimental approach.
From your dendritic cells. Dendritic cells are a type of immune cell. This type of vaccine encourages an immune response to antigens on tumor cells, which helps activate a stronger immune response against the cancer.
Challenges of Therapeutic Cancer Vaccines
While therapeutic cancer vaccines can be an effective method of cancer treatment, there are several challenges to consider:
Immune recognition: The immune system might not recognize cancer cells as easily since they often start as normal cells. This inability to detect the threat makes it hard for the body to respond.
Finding specific antigens: It can be challenging to identify antigens that only present themselves in cancer cells. If non-cancerous cells are affected, too, this could lead to unwanted side effects.
Immune suppression: Cancer cells can produce substances that weaken the immune response. When this happens, immune cells cannot enter the tumor or work well once inside.
Tumor size: Large tumors can make it difficult for immune cells to attack effectively. Cases like this might require combination therapies to improve treatment outcomes.
Weakened immune systems: People with weak immune systems may not respond well to cancer vaccines, which could lead to an overall weaker immune response.
Approved Therapeutic Cancer Vaccines
The U.S. Food and Drug Administration (FDA) has approved several vaccines to treat cancer. These include:
Bacillus Calmette-Guérin (BCG): BCG comes from inactive tuberculosis bacteria and treats early-stage bladder cancer. Doctors place BCG directly into the bladder using a catheter (a thin tube), which boosts the immune system's ability to fight cancer cells in that area.
Nadofaragene firadonevec: This vaccine uses a weakened virus to trigger an immune response in the bladder and is delivered through a catheter. It is administered to adults with early-stage bladder cancer that has been unresponsive to BCG and is likely to recur.
T-VEC: T-VEC is a vaccine for advanced melanoma that cannot be entirely removed with surgery. It uses a modified virus to help the body’s immune system fight the cancer.
Sipuleucel-T: This vaccine is an option for men with advanced prostate cancer. To create Provenge, doctors take some of the patient's immune cells, expose them to a substance from prostate cancer cells, and then put those cells back into the patient’s body.
Continued Research Helps Improve Therapeutic Vaccines
Cancer vaccines, categorized as immunotherapy, are an important area of research in the fight against cancer. This allows for continuous progress, including improved genetic sequencing techniques that help researchers identify more tumor-specific antigens called neoantigens. These neoantigens offer better and new targets for vaccines.
Combination Cancer Therapies
Stopping tumor growth often requires more than a cancer vaccine. As tumors change, they can create molecules that block the work of immune cells. In these cases, combination treatments might be recommended. This means using a therapeutic vaccine with another type of immunotherapy, such as checkpoint inhibitors.
Intratumoral Therapies (In Situ Vaccines)
In situ vaccination uses the patient's tumor as a vaccine. Immune-boosting drugs are injected directly into the tumor, prompting the tumor to present antigens that can activate the immune response. Researchers are exploring this strategy with various immune-activating agents, including oncolytic viruses, bacteria, antibodies, and other molecules.
Oncolytic Virus-Based Vaccines
Oncolytic viruses are another vaccine that can infect and kill cancer cells. Some may even be genetically modified. Vaccines that use these viruses effectively trigger the immune system and act as both an antigen and an adjuvant, making them an attractive option.
The Latest Cancer Treatments & Clinical Research is Available in South Chicago
Affiliated Oncologists is actively involved in cancer research in communities across the greater Chicago area and offers clinical trials through Sarah Cannon Research Institute (SCRI), one of the world’s leading oncology research organizations conducting community-based clinical trials.
If you were diagnosed with cancer, our oncologists are here to create a personalized treatment plan for you. We’ll discuss your diagnosis to see if a cancer vaccine or participation in a clinical trial is right for you. If a cancer vaccine isn't suitable, your oncologist will discuss your best treatment options. Request an appointment at one of our cancer centers in Chicago Ridge, Hazel Crest, Mokena, Oak Lawn, or Orland Park, Illinois.
Categories: Clinical Trials & Research