Cancer Immunotherapy Treatments

Cancer is the second leading cause of death in American, with over half a million deaths from cancer reported in 2009. Cancer chemotherapy treatments were developed in the nineteen hundreds and remain the backbone of current treatments; however, they have some limitations. New immunotherapy cancer treatments, where biologic agents are given to patients to influence the body’s natural immune response, are being researched. Among these immunotherapy treatments are co-inhibition blockade of T cells, and combination blockade treatments together with chemotherapy treatment. This review will discuss T cell activation and the role of T cell coinhibitors such as CTLA-4 and PD-1 in immune system function. It will go through some immune system dysfunctions seen in breast cancer patients. The review will focus on the usage of anti-CTLA-4 and anti-PD-1 antibodies in coinhibition blockade treatments, as well as combination immunotherapy approaches in clinical trials. The mechanism involved in the blockade of T cell coinhibition is important for understanding why this form of immunotherapy is successful. Anti-CTLA-4 and PD-1 antibodies have resulted in objective responses in a good percentage of cancer patients. New combination immunotherapy approaches, as well as immunotherapy treatments in addition to chemotherapy, has been shown to be more effective. Also, the blockade of multiple T cell receptors combined with vaccination in mice has yielded a high survival rate. Most of the material for this paper was located from journals, and extracted via The Touro College Library search engine—primarily through Pubmed. Introduction Cancer is the second leading cause of death in America. The Centers for Disease Control and Prevention reported 567,628 deaths from cancer in 2009. One in six people in the U.S. and Europe will die of cancer (Paul, 1991). Cancer treatment evolution began with ancient physicians using surgery. Little progress was made until the early nineteen hundreds, when radiation therapy and chemotherapy were developed. Until the late 1990s nearly all drugs used in cancer treatment worked by killing cells that were in the process of mitosis. These chemotherapy drugs also killed some normal cells but had a greater effect on cancer cells. Better understanding of the biology of cancer cells has led to the development of a new type of cancer treatment called immunotherapy, where biologic agents like interferons, interleukins, and other cytokines are given to patients to imitate or influence the natural immune response. They function either by directly altering the cancer cell growth, or by acting indirectly to help healthy cells control the cancer (The American Cancer Society, 2012). In adoptive immunotherapy, or cell-transfer therapy, cells involved in immune defense are removed from a cancer patient and “educated” to react against the cancer, or else to enhance the patient’s native ability to kill cancer cells. The cells are then returned to the bloodstream. Molecules that are important in the immune response are administered in combination with the transfer of