A promising and continually evolving form of cancer treatment, cellular immunotherapy builds upon the power of the body’s immune system to target and destroy harmful invaders, such as bacteria, viruses and cancer. More specifically, immune cells known as T cells have certain proteins (receptors) that are able to recognize and bind to antigens, (typically foreign) when presented by other immune system cells (antigen presenting cells). Upon binding, the T cell is activated to destroy cells harboring this antigen.
Although all cancer cells have antigens, T cells only activate to destroy cancer cells when their receptor specifically recognizes the combination of the antigen and the presenting molecule on the surface of the antigen presenting cell. T cells must match the presenting molecules of the antigen presenting cells, which forms the basis for the “matching” that is required when selecting an organ donor. As such, immunotherapy is currently not a “one-size-fits-all” treatment; instead, it must be personalized to meet the precise needs of each patient.
Immunotherapy for blood cancers
One type of cancer immunotherapy is chimeric antigen receptor (CAR) T cell therapy, which is approved by the U.S. Food and Drug Administration (FDA) for treating certain types of blood cancer, such as leukemia and lymphoma. CAR-T cell therapy involves obtaining a sample of T cells from the patient, then bioengineering those cells in a laboratory to express artificial CARs that can identify and attach to tumor cells. The genetically modified cells bypass the need for T cell and receptor matching, which have an enhanced ability to target a specific protein found on certain cancer cells, without the need for antigen presenting cells. After manufacture, the cells are injected into the patient’s bloodstream, where the “supercharged” T cells circulate throughout the patient’s body to find and destroy cancerous cells.
Immunotherapy for solid tumors
Another type of immunotherapy that is currently showing promise is T-cell receptor (TCR) therapy. Like CAR-T cell therapy, TCR therapy involves the modification of T cells in a lab. However, unlike CAR-T cell therapy — which relies on man-made receptors that can only target things on the surface of cells —TCR therapy capitalizes on the natural mechanisms of T cells.
TCR is unique in that it can recognize many types of cancer that have overexpression of a specific antigen within the cell, if it is presented a specific human leukocyte antigen (HLA), which can be found on the surface of tumor cells in the same manner as an antigen presenting cell. Because solid tumor cell surface antigens closely resemble normal tissues, CAR-T cell therapy is more prone to toxicities when targeting solid tumors. As such, TCR therapy may be better suited than CAR-T cell therapy for treating solid tumors, which make up the vast majority of all malignancies. In studies, TCR therapy has effectively destroyed blood, lung, breast, prostate, colon, bone, skin, kidney, ovarian and cervical cancer cells while ignoring healthy cells.
Scientists around the globe, including the renowned research teams at Moffitt Cancer Center, continue to explore the precise molecular mechanisms by which TCR therapy is able to distinguish between cancer cells and healthy cells. At Moffitt, we are excited about the prospect of TCR therapy as a “universal” cancer treatment, which can potentially benefit countless cancer patients. With an aim to one day find a cure, we are committed to continually evaluating and developing immunotherapies for treating both blood cancers and solid tumors.
Medically reviewed by Frederick Locke, MD, vice chair, Department of Blood and Marrow Transplant and Cellular Immunotherapy
If you have questions or would like to learn more about cancer immunotherapies, call 1-888-663-3488 or complete our new patient registration form online to rapidly connect with a cancer specialist at Moffitt.