Your body’s immune system Overview of the Immune System The immune system is your body's defense system. It helps protect you from illness and infection. The immune system's job is to attack things that don’t belong in your body, including: Germs... read more can often find a cancer cell and destroy it before the cancer grows or spreads. Your immune system is the network of cells, tissues, and organs in your body that helps protect you from illness and infection. Your immune system can often recognize that cancer cells are abnormal and attack them.
Cancer spreads more easily in people who have a weak immune system or problems with their immune system. This can happen if you:
However, even when your immune system is working well, sometimes it can’t find and destroy all cancer cells. Sometimes your cancer is too large for the immune system to destroy it.