Immunotherapy to fight cancer: What is it and how does it work?
Let’s start by refreshing our understanding of how our immune system works (in case you can't recall your high school biology course in perfect detail).
Our immune system fights invaders, such as germs, throughout our body. Another important function of our immune system is to recognize and destroy cancer cells that may form within our body. Our immune system naturally gets weak, or tired, as we age. Additionally, cancer cells can develop an ability to hide from the immune system, or can disable the immune system from acting against them. Combine a tired immune system with a cancer that turns it off (or hides from it), and the result can be particularly troubling for the older population.
The goal of immunotherapy for cancer is to induce our immune system to recognize and kill cancer cells. Over the past few decades, immunotherapy has become an important part of treating some types of cancer.
How our immune system is activated and how cancer cells have found a way around our immune system:
- When our immune system sees something foreign, it receives a series of signals
- + Signal 1 – get ready
- + Signal 2 – confirms threat and activates the immune system to attack
- - Signal – a negative signal (also known as a checkpoint) is sent to indicate the harmful entity has been controlled and it is time to shut off
- Cancer cells have evolved to display a protein on their surface that sends the negative signal to the immune system, preventing it from activating and eliminating the cancer cells
Immunotherapy tries to induce our immune system to recognize and kill the cancer cells by introducing a checkpoint inhibitor. Checkpoint inhibitors are drugs that interfere with the cascade of signals sent by the cancer cell to deactivate the immune system.
“What we are trying to do is to block the signal from the cancer cell so that our immune system activates as it normally would,” says hematologist J.C. Villasboas, M.D.
“Immunotherapy has been a homerun for classic Hodgkin’s lymphoma,” says Dr. Villasboas. “But the other 90 percent of lymphomas have had limited activity when treated with checkpoint inhibitors alone.”
Coming up next, we will look in to what happens when checkpoint inhibitors alone are not enough to activate our immune system. Dr. Villasboas and Dr. Stephen Ansell are on the forefront of research in dual-immunomodulation, a technique that combines both checkpoint inhibitors and immune system accelerants. Discover opportunities and learn more about Clinical Trials at Mayo Clinic.