Immune System and Cancer
Immune system
and cancer

How do cancer cells grow despite immune responses?

Cancer develops from normal cells in the body that have changed or mutated. The immune system may not see the cancer as a foreign invader so it cannot work against the cancer properly. In addition, the immune system may not be strong enough to fight the cancer.

Cancer cells have many ways to evade detection and destruction by the immune system. For example, cancer cells can:5

  • Undergo genetic changes that cause them to reduce the expression of tumor antigens on their surface, making them less “visible” to the immune system;
  • Have proteins on their surface that inactivate immune cells;
  • Induce normal cells around the tumor to release substances that suppress immune responses and that promote tumor cell proliferation and survival.

Understanding how cancer cells avoid the immune system has resulted in the availability of a new type of treatment approach, immunotherapy. Immunotherapy is transforming how treatments work for several types of cancer, including lung and bladder cancer.