Immuno-oncology is the study and development of treatments that take advantage of the body’s immune system to fight cancer.

Our immune system is a complex network of organs, cells and molecules that protects us from foreign substances—such as bacteria, fungi and viruses—that can cause infection. In addition to finding and destroying foreign substances, the immune system can also locate and attack abnormal cells.

There are two main parts of the immune system:

  • Innate immunity, a defense system we are born with, is the ability of the body to immediately protect itself against foreign organisms and toxins.
  • Adaptive immunity is a learned defense system that develops in response to exposure to a specific foreign substance. The adaptive immune system works in one of two ways:
    • Humoral, also called antibody-mediated, in which B-cells (a type of white blood cell called a lymphocyte) make antibodies (specific blood proteins) that identify and destroy foreign substances.
    • Cell-mediated, in which T-cells (another type of white blood cell or lymphocyte) identify and destroy abnormal cells, including those that are cancerous.

Both an overactive and an underactive immune system can be harmful. Our growing understanding of the health benefits of a balanced immune system has led to the development of immunotherapies as a treatment approach for many types of cancer.