Targeted therapy is a type of cancer treatment that targets proteins that control how cancer cells grow, divide, and spread. It is the foundation of precision medicine. As researchers learn more about the DNA changes and proteins that drive cancer, they are better able to design treatments that target these proteins.
Most targeted therapies are either small-molecule drugs or monoclonal antibodies.
Small-molecule drugs are small enough to enter cells easily, so they are used for targets that are inside cells.
Monoclonal antibodies, also known as therapeutic antibodies, are proteins produced in the lab. These proteins are designed to attach to specific targets found on cancer cells. Some monoclonal antibodies mark cancer cells so that they will be better seen and destroyed by the immune system. Other monoclonal antibodies directly stop cancer cells from growing or cause them to self-destruct. Still others carry toxins to cancer cells. Learn more about monoclonal antibodies.
How does targeted therapy work against cancer?
Most types of targeted therapy help treat cancer by interfering with specific proteins that help tumors grow and spread throughout the body. This is different from chemotherapy, which often kills all cells that grow and divide quickly. The following explains the different ways that targeted therapy treats cancer.
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. Learn more about immunotherapy to treat cancer.
Stop cancer cells from growing by interrupting signals that cause them to grow and divide without order. 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. To grow beyond a certain size, tumors need to form new blood vessels in a process called angiogenesis. The tumor sends signals that start angiogenesis. Some targeted therapies called angiogenesis inhibitors 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 cell-killing substances such as toxins, chemotherapy drugs, or 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, which is called apoptosis.
Starve cancer of 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. Learn more about hormone therapy for prostate cancer and hormone therapy for breast cancer.