Cancer immunotherapy

Cancer immunotherapy
Peptide epitope of CD20 bound to rituximab's FAB
Specialty	Tumor immunology
[edit on Wikidata]

Cancer immunotherapy (immuno-oncotherapy) is the stimulation of the immune system to treat cancer, improving the immune system's natural ability to fight the disease.^[1] It is an application of the fundamental research of cancer immunology (immuno-oncology) and a growing subspecialty of oncology.

Cancer immunotherapy exploits the fact that cancer cells often have tumor antigens, molecules on their surface that can bind to antibody proteins or T-cell receptors, triggering an immune system response. The tumor antigens are often proteins or other macromolecules (e.g., carbohydrates). Normal antibodies bind to external pathogens, but the modified immunotherapy antibodies bind to the tumor antigens marking and identifying the cancer cells for the immune system to inhibit or kill. The clinical success of cancer immunotherapy is highly variable between different forms of cancer; for instance, certain subtypes of gastric cancer react well to the approach whereas immunotherapy is not effective for other subtypes.^[2]

Major types of cancer immunotherapy include immune checkpoint inhibitors, which block inhibitory pathways such as PD-1/PD-L1 and CTLA-4 to enhance T cell activity against tumors. These therapies have shown effectiveness in treating cancers such as melanoma and lung cancer.^[3][4][5]

Adoptive cell therapies, including chimeric antigen receptor (CAR) T cell therapy, involve modifying a patient’s immune cells to recognize cancer-specific antigens. These therapies have been particularly effective in certain blood cancers.^[4][5][6] Natural killer cell (NK) therapies and CAR-NK cell approaches are also being explored, leveraging NK cells' innate ability to target tumor cells.^[5][6] Other strategies include cancer vaccines, which aim to provoke an immune response against tumor-associated antigens, and may be either preventive or therapeutic.^[5] Immunomodulatory agents such as cytokines (e.g., interleukin-2, interferon-alpha) and Bacillus Calmette-Guerin (BCG) are used to enhance immune activity or alter the tumor microenvironment.^[5] Oncolytic virus therapies, which employ engineered viruses to selectively kill cancer cells while promoting systemic immunity, are also under investigation.^[3]

In 2018, American immunologist James P. Allison and Japanese immunologist Tasuku Honjo received the Nobel Prize in Physiology or Medicine for their discovery of cancer therapy by inhibition of negative immune regulation.^[7]