Therapies that target the blood supply to tumors, known as anti-angiogenic therapies, aim to inhibit the formation of new blood vessels. By blocking angiogenesis, these treatments can restrict the tumor's access to oxygen and nutrients, thereby slowing its growth. Drugs such as bevacizumab (Avastin) are examples of anti-angiogenic agents used in cancer treatment. However, resistance to these therapies can develop, making it a continuous area of research.