Precision medicine or targeted therapy is a type of cancer treatment that targets proteins that control how cancer cells grow, divide, and spread. As researchers learn more about the DNA changes and proteins that drive cancer, they are better able to design promising treatments that target these proteins.

Most types of targeted therapy help treat cancer by interfering with specific proteins that help tumors grow and spread throughout the body. They treat cancer in many ways. They can:

• Help the immune system destroy cancer cells. One reason that cancer cells thrive is because they can hide from your immune system. Certain targeted therapies can mark cancer cells so it is easier for the immune system to find and destroy them. Other targeted therapies help boost your immune system to work better against cancer.

• Stop cancer cells from growing. Healthy cells in your body usually divide to make new cells only when they receive strong signals to do so. These signals bind to proteins on the cell surface, telling the cells to divide. This process helps new cells form only as your body needs them. But, some cancer cells have changes in the proteins on their surface that tell them to divide whether or not signals are present. Some targeted therapies interfere with these proteins, preventing them from telling the cells to divide. This process helps slow cancer’s uncontrolled growth.

• Stop signals that help form blood vessels. Tumors need to form new blood vessels to grow beyond a certain size. In a process called angiogenesis, these new blood vessels form in response to signals from the tumor. Some targeted therapies called angiogenesis inhibitors are designed to interfere with these signals to prevent a blood supply from forming. Without a blood supply, tumors stay small. Or, if a tumor already has a blood supply, these treatments can cause blood vessels to die, which causes the tumor to shrink. Learn more about Angiogenesis Inhibitors.

Deliver cell-killing substances to cancer cells. Some monoclonal antibodies are combined with toxins, chemotherapy drugs, and radiation. Once these monoclonal antibodies attach to targets on the surface of cancer cells, the cells take up the cell-killing substances, causing them to die. Cells that don’t have the target will not be harmed.

• Cause cancer cell death. Healthy cells die in an orderly manner when they become damaged or are no longer needed. But, cancer cells have ways of avoiding this dying process. Some targeted therapies can cause cancer cells to go through this process of cell death.

• Starve cancer of the hormones it needs to grow. Some breast and prostate cancers require certain hormones to grow. Hormone therapies are a type of targeted therapy that can work in two ways. Some hormone therapies prevent your body from making specific hormones. Others prevent the hormones from acting on your cells, including cancer cells.