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  • What Is Immunotherapy
  • Immunotherapy FAQ
  • Immune System vs Cancer
  • CRI's Impact

What Is Cancer Immunotherapy?

Reviewed By: Ezra Cohen, M.D.
UC San Diego Health

What is immunotherapy? Cancer immunotherapy, also known as immuno-oncology, is a form of cancer treatment that uses the power of the body’s own immune system to prevent, control, and eliminate cancer.

Immunotherapy can:

  • Educate the immune system to recognize and attack specific cancer cells
  • Boost immune cells to help them eliminate cancer
  • Provide the body with additional components to enhance the immune response

Cancer immunotherapy comes in a variety of forms, including targeted antibodies, cancer vaccines, adoptive cell transfer, tumor-infecting viruses, checkpoint inhibitors, cytokines, and adjuvants. Immunotherapies are a form of biotherapy (also called biologic therapy or biological response modifier (BRM) therapy) because they use materials from living organisms to fight disease. Some immunotherapy treatments use genetic engineering to enhance immune cells’ cancer-fighting capabilities and may be referred to as gene therapies. Many immunotherapy treatments for preventing, managing, or treating different cancers can also be used in combination with surgery, chemotherapy, radiation, or targeted therapies to improve their effectiveness.

Unleashing the power of the immune system is a smart way to fight cancer:

  1. The immune system is precise, so it is possible for it to target cancer cells exclusively while sparing healthy cells.
  2. The immune system can adapt continuously and dynamically, just like cancer does, so if a tumor manages to escape detection, the immune system can re-evaluate and launch a new attack.
  3. The immune system’s “memory” allows it to remember what cancer cells look like, so it can target and eliminate the cancer if it returns.

Why immunotherapy

Immunotherapies have been approved in the United States and elsewhere to treat a variety of cancers and are prescribed to patients by oncologists. These approvals are the result of years of research and testing designed to demonstrate the effectiveness of these treatments. Immunotherapies are also available through clinical trials, which are carefully controlled and monitored studies involving patient volunteers.

Immunotherapy doesn’t always work for every patient, and certain types of immunotherapy are associated with potentially severe but manageable side effects. Scientists are developing ways to determine which patients are likely to respond to treatment and which aren’t. This research is leading to new strategies to expand the number of patients who may potentially benefit from treatment with immunotherapy.

Although scientists haven’t yet mastered all the immune system’s cancer-fighting capabilities, immunotherapy is already helping to extend and save the lives of many cancer patients. Immunotherapy holds the potential to become more precise, more personalized, and more effective than current cancer treatments—and potentially with fewer side effects. Learn more about how you can support new breakthroughs in cancer immunotherapy research

Frequently Asked Immunotherapy Questions

What types of cancers can immunotherapy treat?

Immunotherapy has potential to treat all cancers.

Immunotherapy enhances the immune system’s ability to recognize, target, and eliminate cancer cells, wherever they are in the body, making it a potential universal answer to cancer.

Immunotherapy has been approved in the U.S. and elsewhere as a first-line of treatment for several cancers, and may also be an effective treatment for patients with certain cancers that are resistant to prior treatment. Immunotherapy may be given alone or in combination with other cancer treatments. As of December 2019, the FDA has approved immunotherapies as treatments for nearly 20 cancers as well as cancers with a specific genetic mutation

Learn more about immunotherapies for different types of cancer

Does immunotherapy have any side effects?

Immunotherapy may be accompanied by side effects that differ from those associated with conventional cancer treatments, and side effects may vary depending on the specific immunotherapy used. In most cases, potential immunotherapy-related side effects can be managed safely as long as the potential side effects are recognized and addressed early.

  • Cancer immunotherapy treats the patient—by empowering their immune system—rather than the disease itself like chemotherapy and radiation. Patients may be tested for biomarkers that may indicate whether cancer immunotherapy would be an effective treatment.
  • Side effects of immunotherapy may results from stimulation of the immune system and may range from minor inflammation and flu-like symptoms, to major, potentially life-threatening conditions similar to autoimmune disorders.
  • Common side effects may include but are not limited to skin reactions, mouth sores, fatigue, nausea, body aches, headaches, and changes in blood pressure.

Conventional cancer treatments also have a range of side effects with a wide range of severity.

  • Chemotherapy is intended to target fast-growing cancer cells, so it may damage other fast-growing normal cells in your body. Common side effects may include but are not limited to hair loss, nausea, diarrhea, skin rash, and fatigue.
  • Radiation uses radioactive particles to destroy cancer cells in a localized area, so it may damage other healthy cells in that area. Side effects may be associated with the area of treatment, such as difficulty breathing when aimed at the chest, or nausea when aimed at the stomach. Skin problems and fatigue are common.
  • The goal of surgery is to remove the cancerous tumor or tissue and varies according to the type of surgery performed. Common side effects may include but are not limited to pain, fatigue, swelling, numbness, and risk of infection.

Learn more about immunotherapy side effects

How long does immunotherapy last?

Cancer immunotherapy offers the possibility for long-term control of cancer.

Immunotherapy can “train” the immune system to remember cancer cells. This “immunomemory” may result in longer-lasting and potentially permanent protection against cancer recurrence.

Clinical studies on long-term overall survival have shown that the beneficial responses to cancer immunotherapy treatment can be durable—that is, they continue even after treatment is completed.

How long has immunotherapy been used as a cancer treatment?

Cancer immunotherapy originated in the late 1890s with a cancer surgeon named Dr. William B. Coley (1862–1936). He discovered that infecting cancer patients with certain bacteria sometimes resulted in tumor regression and even some complete remissions. Advances in cancer immunology since Coley’s time have revealed that, in patients that responded to his treatment, his bacterial toxin therapy stimulated their immune systems to attack the tumors.

While Coley’s approach was largely dismissed during his lifetime, his daughter, Helen Coley Nauts, discovered his old notebooks and founded the Cancer Research Institute in 1953 to support research into his theory. In 1990, the FDA approved the first cancer immunotherapy, a bacteria-based tuberculosis vaccine called Bacillus Calmette-Guérin (BCG), which was shown to be effective for patients with bladder cancer.

Visit the Timeline of Immunotherapy

What is the relationship between cancer and the immune system?

While many of our cells grow and divide naturally, this behavior is tightly controlled by a variety of factors, including the genes within cells. When no more growth is needed, cells are told to stop growing.

Unfortunately, cancer cells acquire defects that cause them to ignore these stop signals, and they grow out of control. Because cancer cells grow and behave in abnormal ways, this can make them stand out to the immune system, which can recognize and eliminate cancer cells through a process called immunosurveillance.

However, this process isn't always successful. Sometimes cancer cells develop ways to evade and escape the immune system, which allows them to continue to grow and metastasize, or spread to other organs. Therefore, immunotherapies are designed to boost or enhance the cancer-fighting capabilities of immune cells and tip the scales in the immune system's favor.

Learn more about how the immune system functions below

What types of immunotherapy treatments are there?

Immunotherapy treatments can be broken down into five types:

  1. Targeted antibodies are proteins produced by the immune system that can be customized to target specific markers (known as antigens) on cancer cells, in order to disrupt cancerous activity, especially unrestrained growth. Some targeted antibody-based immunotherapies, known as antibody-drug conjugates (ADCs), are equipped with anti-cancer drugs that they can deliver to tumors. Others, called bi-specific T cell-engaging antibodies (BiTEs), bind both cancer cells and T cells in order to help the immune system respond more quickly and effectively. All targeted antibody therapies are currently based on monoclonal antibodies (clones of a parent bonding to the same marker(s)).
  2. Adoptive cell therapy takes a patient’s own immune cells, expands or otherwise modifies them, and then reintroduces them to the patient, where they can seek out and eliminate cancer cells. In CAR T cell therapy, cancer-fighting T cells are modified and equipped with specialized cancer-targeting receptors known as CARs (chimeric antigen receptors) that enable superior anti-cancer activity. Natural killer cells (NKs) and tumor infiltrating lymphocytes (TILs) can also be enhanced and reinfused in patients.
  3. Oncolytic virus therapy uses viruses that are often, but not always, modified in order to infect tumor cells and cause them to self-destruct. This can attract the attention of immune cells to eliminate the main tumor and potentially other tumors throughout the body.
  4. Cancer vaccines are designed to elicit an immune response against tumor-specific or tumor-associated antigens, encouraging the immune system to attack cancer cells bearing these antigens. Cancer vaccines can be made from a variety of components, including cells, proteins, DNA, viruses, bacteria, and small molecules. Some versions are engineered to produce immune-stimulating molecules. Preventive cancer vaccines inoculate individuals against cancer-causing viruses and bacteria, such as HPV or hepatitis B.
  5. Immunomodulators govern the activity of other elements of the immune system to unleash new or enhance existing immune responses against cancer. Some, known as antagonists, work by blocking pathways that suppress immune cells. Others, known as agonists, work by stimulating pathways that activate immune cells. Checkpoint inhibitors target the molecules on either immune or cancer cells that tell them when to start or stop attacking a cancer cell. Cytokines are messenger molecules that regulate maturation, growth, and responsiveness. Interferons (IFN) are a type of cytokine that disrupts the division of cancer cells and slows tumor growth. Interleukins (IL) are cytokines that help immune cells grow and divide more quickly. Adjuvants are immune system agents that can stimulate pathways to provide longer protection or produce more antibodies (they are often used in vaccines, but may also be used alone).

Learn more about how different facets of the immune system fight cancer.

What is the difference between immunotherapy and chemotherapy?

Chemotherapy is a direct form of attack on rapidly-dividing cancer cells, but this can affect other rapidly dividing cells including normal cells. When patients respond, the treatment’s effects happen immediately. These direct effects of chemotherapy, however, last only as long as treatment continues.

Immunotherapy treats the patient’s immune system, activating a stronger immune response or teaching the immune system how to recognize and destroy cancer cells. Immunotherapy may take more time to have an effect, but those effects can persist long after treatment ceases.

Learn more about immunotherapy versus chemotherapy

Who can receive immunotherapy? What immunotherapies are approved for standard care?

As of May 2021, the U.S. Food and Drug Administration had approved over 50 immunotherapies that together cover almost every major cancer type:

  1. Aldesleukin (immunomodulator) for kidney cancer and melanoma
  2. Alemtuzumab (targeted antibody) for leukemia
  3. Atezolizumab (checkpoint inhibitor) for bladder, breast, liver, and lung cancer, and melanoma
  4. Avelumab (checkpoint inhibitor) for bladder and skin cancer (Merkel cell carcinoma)
  5. Axicabtagene ciloleucel (CAR T cell therapy) for lymphoma
  6. Bacillus Calmette-Guérin [BCG] (vaccine) for bladder cancer
  7. Belantamab mafodotin-blmf (antibody-drug conjugate) for multiple myeloma
  8. Bevacizumab (targeted antibody) for brain, cervical, colorectal, kidney, liver, lung, and ovarian cancer
  9. Blinatumomab (bi-specific T cell-engaging antibody) for leukemia
  10. Brentuximab vedotin (antibody-drug conjugate) for lymphoma
  11. Brexucabtagene autoleucel (CAR T cell therapy) for lymphoma
  12. Cemiplimab (checkpoint inhibitor) for skin cancer (basal cell carcinoma and cutaneous squamous cell carcinoma) and lung cancer 
  13. Cetuximab (targeted antibody) for colorectal and head and neck cancer
  14. Daratumumab (targeted antibody) for multiple myeloma
  15. Denosumab (targeted antibody) for sarcoma
  16. Dinutuximab (targeted antibody) for pediatric neuroblastoma
  17. Dostarlimab (checkpoint inhibitor) for uterine (endometrial) cancer
  18. Durvalumab (checkpoint inhibitor) for bladder and lung cancer
  19. Elotuzumab (targeted antibody) for multiple myeloma
  20. Enfortumab vedotin-ejfv (antibody-drug conjugate) for bladder cancer
  21. Gemtuzumab ozogamicin (antibody-drug conjugate) for leukemia
  22. Granulocyte-macrophage colony-stimulating factor, or GM-CSF (immunomodulator) for neuroblastoma
  23. Hepatitis B Vaccine (Recombinant) (preventive vaccine) for liver cancer
  24. Human Papillomavirus Quadrivalent (Types 6, 11, 16, 18) Vaccine, Recombinant (preventive vaccine) for cervical, vulvar, vaginal, and anal cancer
  25. Human Papillomavirus 9-valent Vaccine, Recombinant (preventive vaccine) for cervical, vulvar, vaginal, anal, and throat cancer
  26. Human Papillomavirus Bivalent (Types 16 and 18) Vaccine, Recombinant (preventive vaccine) for cervical cancer
  27. Ibritumomab tiuxetan (antibody-drug conjugate) for lymphoma
  28. Idecabtagene vicleucel (CAR T cell therapy) for multiple myeloma
  29. Imiquimod (immunomodulator) for skin cancer
  30. Inotuzumab ozogamicin (antibody-drug conjugate) for leukemia
  31. Interferon alfa-2a (immunomodulator) for sarcoma and leukemia
  32. Interferon alfa-2b (immunomodulator) for leukemia
  33. Ipilimumab (checkpoint inhibitor) for melanoma, mesothelioma, liver, and lung cancer
  34. Isatuximab (targeted anytibody) for multiple myeloma
  35. Lisocabtagene maraleucel (CAR T cell therapy) for lymphoma 
  36. Loncastuximab tesirine​ (antibody-drug conjugate) for lymphoma 
  37. Mogamulizumab (targeted antibody) for lymphoma
  38. Naxitamab-gqgk (targeted antibody) for neuroblastoma
  39. Necitumumab (targeted antibody) for lung cancer
  40. Nivolumab (checkpoint inhibitor) for bladder, colorectal, esophageal, GEJ, head and neck, kidney, liver, lung, and stomach cancer, lymphoma, melanoma, and mesothelioma
  41. Obinutuzumab (targeted antibody) for leukemia and lymphoma
  42. Ofatumumab (targeted antibody) for leukemia
  43. Olaratumumab (targeted antibody) for sarcoma
  44. Panitumumab (targeted antibody) for colorectal cancer
  45. Peginterferon alfa-2b (immunomodulator) for melanoma
  46. Pembrolizumab (checkpoint inhibitor) for bladder, breast, colorectal, esophageal, head and neck, stomach, liver, uterine, and lung cancer as well as lymphoma, melanoma, Merkel cell carcinoma, cutaneous squamous cell carcinoma, and any MSI-H or TMB-H solid cancer regardless of origin
  47. Pertuzumab (targeted antibody) for breast cancer
  48. Pexidartinib (immunomodulator) for tenosynovial giant cell tumor
  49. Polatuzumab vedotin (antibody-drug conjugate) for non-Hodgkin lymphoma
  50. Poly ICLC (immunomodulator) for skin cancer
  51. Ramucirumab (targeted antibody) for colorectal, esophageal, lung, and stomach cancer
  52. Rituximab (targeted antibody) for leukemia and lymphoma
  53. Sacituzumab govitecan-hziy (antibody-drug conjugate) for breast cancer
  54. Sipuleucel-T (vaccine) for prostate cancer
  55. Tafasitamab (targeted antibody) for lymphoma
  56. Tisagenlecleucel (CAR T cell therapy) for leukemia (including pediatric)
  57. Trastuzumab (targeted antibody) for breast and esophageal cancer
  58. Trastuzumab deruxtecan (antibody-drug conjugate) for breast cancer
  59. Trastuzumab emtansine (antibody-drug conjugate) for breast cancer
  60. T-VEC (oncolytic virus) for melanoma

New immunotherapies are being developed and immunotherapy clinical trials are under way in nearly all forms of cancer.

Can people with autoimmune diseases and cancer be treated with immunotherapy?

People with mild autoimmune diseases are able to receive most immunotherapies. Typically, autoimmune treatment is adjusted and a checkpoint immunotherapy, such as those targeting the PD-1/PD-L1 pathway, is used. However, each patient should speak with his or her doctor regarding the options that are most appropriate.

Can people with HIV be treated with immunotherapy?

People with HIV who are receiving effective anti-viral treatment and whose immune systems are functioning normally may respond to cancer immunotherapy and are therefore eligible to receive immunotherapy, both as standard of care and as part of a clinical trial.

How can I receive immunotherapy treatment?

The administration and frequency of immunotherapy regimens vary according to the cancer, drug, and treatment plan. Clinical trials can offer many valuable treatment opportunities for patients. Discuss your clinical trial options with your doctor.

Find an immunotherapy clinical trial

How can I tell whether immunotherapy is working?

Immunotherapy treatments may take longer to produce detectable signs of tumor shrinkage compared to traditional treatments. Sometimes tumors may appear to grow on scans before getting smaller, but this apparent swelling may be caused by immune cells infiltrating and attacking the cancer. Many patients who experience this phenomenon, known as pseudoprogression, often report feeling better overall.

In certain cancer types, immune-related side effects may be linked with treatment success—specifically, melanoma patients who develop vitiligo (blotched loss of skin color)—but for the vast majority of patients, no definitive link has been established between side effects and immunotherapy’s effectiveness.

How is the Cancer Research Institute involved in the development of immunotherapy?

For more than 65 years, the Cancer Research Institute (CRI) has been the pioneer in advancing immune-based treatment strategies against cancer. It is the world's leading nonprofit organization dedicated exclusively to saving more lives by fueling the discovery and development of powerful immunotherapies for all types of cancer. 

CRI provides financial support to scientists at all stages of their careers along the entire spectrum of immunotherapy research and development: from basic discoveries in the lab that shed light on the fundamental components and mechanisms of the immune system and its relationship to cancer, to efforts focused on translating those discoveries into lifesaving treatments that are then tested in clinical trials for cancer patients.

Learn about CRI's impact

Boosting the Body's Immune System to Fight Cancer

Immunotherapy treatment harnesses the body's natural strength to fight cancer—
empowering the immune system to conquer more types of cancer and save more lives.

bind to antigens on threats in the body (e.g., bacteria, viruses, cancer cells) and mark cells for attack and destruction by other immune cells
B Cells
release antibodies to defend against threats in the body
CD4+ Helper T Cells
send “help” signals to the other immune cells (e.g., B cells and CD8+ killer T cells) to make them more efficient at destroying harmful invaders
CD8+ Killer T Cells
destroy thousands of virus-infected cells each day, and are also able to seek out and destroy cancer cells
help immune cells communicate with each other to coordinate the right immune response
Dendritic Cells
digest foreign and cancerous cells and present their proteins to immune cells that can destroy them
engulf and destroy bacteria, virus-infected cells, and cancer as well as present antigens to other immune cells
Natural Killer Cells
recognize and destroy virus-infected and tumor cells quickly without the help of antibodies and "remember" these threats
Regulatory T Cells
provide the checks and balances to ensure that the immune system does not overreact

How the Immune System Works

Organs, tissues, and glands around your body coordinate the creation, education, and storage of key elements in your immune systems.

Thin tube about 4 to 6 inches long in the lower right abdomen. The exact function is unknown; one theory is that it acts as a storage site for "good" digestive bacteria
Bone Marrow
Soft, sponge-like material found inside bones. Contains immature cells that divide to form more blood-forming stem cells, or mature into red blood cells, white blood cells (B cells and T cells), and platelets
Cells lining this set of organs and glands, as well as the bacteria throughout it, influence the balance of the immune system.
Lymph Nodes
Small glands located throughout the body that filter bacteria, viruses, and cancer cells, which are then destroyed by special white blood cells. Also the site where T cells are "educated" to destroy harmful invaders in your body
This organ's receptors detect bacteria and viruses. Nasal mucus catches these pathogens so the immune system can learn to defend against them.
This organ is not only a physical barrier against infection, but also contains dendritic cells for teaching the rest of the body about new threats. The skin microbiome is also an important influence the balance of the immune system.
Organ located to the left of the stomach. Filters blood and provides storage for platelets and white blood cells. Also serves as a site where key immune cells (B cells) multiply in order to fight harmful invaders
A set of organs that can stop germs entering the body through the mouth or the nose. They also contain a lot of white blood cells.
Thymus Gland
Small gland situated in the upper chest beneath the breastbone. Functions as the site where key immune cells (T cells) mature into cells that can fight infection and cancer
Immunotherapy Matters, For One and All

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Updated October 2020

*Immunotherapy results may vary from patient to patient.