Illustration of x-ray of human chest with immunotherapy cells

Immunotherapy

What is immunotherapy?

Image of human cells

Immunotherapy boosts a person’s own immune system to combat lung cancer, helping the body to do what it’s built to do rather than attacking cancer directly. It’s a relatively new development in cancer treatments.

How immunotherapy works is in two ways:

  • Immunotherapy drugs enable the patient's immune system to attack cancer cells.
  • Manmade immune system proteins can also be given to fight cancer cells.

Types of immunotherapy

Immune Checkpoint Inhibitors Checkpoint inhibitors basically "take the brakes off" a patient's immune system so that it recognises and destroys cancer cells. The limitation of checkpoint inhibitors is that they are effective for only a small population.
Cancer Vaccines Cancer vaccines work to prevent or to combat cancer in the body. These vaccines are administered into the body to spur an immune response against cancer cells. Research into such vaccines, also known as therapeutic cancer vaccines, has the potential to uncover an anti-cancer vaccine.
Adoptive Cell Transfer ACT extracts and uses the patient’s own immune cells to treat his or her cancer. There are several types of ACT, including CAR (chimeric antigen receptor) T-cell treatment currently undergoing various trials for different types of cancers—including lung cancer.

The role of PD-1 in cancer

The human immune system works by distinguishing normal healthy cells in the body from foreign cells that could harm the body, and attacking these foreign cells. What the immune system relies on are checkpoints—molecules on certain immune cells that regulate the immune response.

Cancer cells sometimes disguise themselves or block the immune system. The immune system controls activity of T cells (cancer-fighting lymphocytes) through the PD-1 pathway. But some cancer cells block T cell attack by taking control of the pathway.

PD-1 is a checkpoint protein on T cells. It normally acts as an "off switch" that helps keep the T cells from attacking other cells in the body. How it does this is by attaching to PD-L1, a protein on some normal (and cancer) cells. When this binding happens, a signal is sent to stop the T cell from attacking the other cell. Some cancer cells possess large amounts of PD-L1 and are therefore able to avoid T cell attack. These cancer cells are then free to grow and metastasize.

References:
My Onco: About Immunotherapy.
Retrieved Nov 2017 from https://www.myonco.be/immuno/patient/about/Immuno-therapy;
American Cancer Society - Immunotherapy for non-small cell lung cancer.
Retrieved Nov 2017 from https://www.cancer.org/cancer/non-small-cell-lung-cancer/treating/immunotherapy.html;
American Cancer Society: Types of cancer immunotherapy.
Retrieved Nov 2017 from https://www.cancer.org/treatment/treatments-and-side-effects/treatment-types/immunotherapy/what-is-immunotherapy.html