Because cancer begins with a normal cell from within your own body, your immune system doesn't detect cancer cells as being abnormal. In the instance of cancer, your body doesn't see the cells as “foreign” nor try to attack or destroy cancer cells. Through biological therapy, also called immunotherapy, scientists are testing different ways to help your immune system recognize cancer cells as invaders. Essentially, biological therapies use your own body’s immune system to fight cancer or lessen the side effects caused by cancer treatments.

Some of these therapies include:

• Interferons are types of cytokines that occur naturally in the body. Cytokines are proteins produced by white blood cells and that act as messengers between cells. They regulate the intensity and duration of immune responses and are involved in cell-to-cell communication. Researchers believe that some interferons may stimulate Natural Killer cells, T cells and macrophages, boosting the immune system’s anticancer function.
  
  
• Interleukins are also cytokines that occur naturally in the body. Interleukins stimulate growth and activity of immune cells, such as lymphocytes, which can destroy cancer cells. Researchers continue to study the benefits of interleukins to treat a number of cancers, including ovarian cancer.
  
  
• Colony stimulating factors [CSFs] do not affect the cancer cell directly but do encourage bone marrow stem cells to divide and develop into white blood cells, platelets and red blood cells. Bone marrow is critical to the body’s immune system because it is the source of all blood cells. CSFs are often used in combination with chemotherapy, allowing for higher doses of chemotherapy without increasing the risk of infection or the need for a transfusion.
  
  
• Monoclonal antibodies - these substances, made in the laboratory, recognize and attach to specific receptors on the outside of cancer cells, which stop the cell from sending the signal to divide or mark the cell for attack by the immune system. As an e xample, trastuzumab [Herceptin] is a monoclonal antibody and is used to treat breast cancer that overexpresses a protein called HER-2.
  
  
• Gene therapy introduces genetic material into a person’s cells to fight disease. For example, a gene may be inserted into an immune cell to enhance it’s ability to recognize and attack cancer cells.
  
  
• Cancer vaccines. Vaccines are designed to treat cancers by encouraging the patient’s immune system to recognize cancer cells. These vaccines can have minimal side effects since the vaccine is targeting the cancer cells and not healthy tissue.
  

Targeted therapies

Targeted therapies interfere with the proteins and other molecules involved in the growth and development of cancer cells in an attempt to reverse the defects in these cells. For instance, a defect in cancer cells enables them to grow and divide without dying. By reversing that defect, cancer cells could, in theory, be induced to die. Different targeted therapies focus on different points in cancer cells' development and include:

• Angiogenesis inhibitors . Angiogenesis is the formation of new blood vessels. Many tumors build new blood vessels to help them grow and spread. Angiogenesis inhibitors, therefore, prevent new blood vessel formation. An example of an angiogenesis inhibitor is bevacizumab [Avastin].
  
  
• Enzyme inhibitors . Enzymes make biologic processes happen faster and are often key junctions in the signaling pathways, which make them popular drug targets. Many new treatments inhibit the action of a group of enzymes called kinases. Examples: imatinib [Gleevec], gefitinib [Iressa] and erlotinib [Tarceva].
  
  
• Small molecule drugs . These drugs are designed to inhibit pathways for growth or proliferation within tumor cells. An example of this type of targeted therapy is Imatinib [Gleevac] which is currently the standard of therapy for chronic myelogenous leukemia.
  
  
• Proteasome inhibitors. Proteasomes are groups of enzymes that break down proteins, and this process helps maintain the cell. An example of a proteasome inhibibor is Bortezomib [Velcade].