443 - Use of Surgery and Immunotherapy to Treat Cancer

continue today with the use of bone marrow transplant as a treatment for hematological cancers. Another researcher at this time, Lloyd J. Old, realized that cancer cells are unique and different from normal cells and that this difference can be recognized by the human immune system. Professor Old theorized that immunotherapy would be used with chemo- therapy, radiation, and surgery to treat cancer patients. In 1981, the first vaccine based on a single cell surface antigen became available – a hepatitis B vaccine – propelling the research to current developments. 4 Finally, as a result of research, which began in the 1950s, scientists determined the body’s lymphocytes might act as soldiers to identify and eliminate cancer cells. Experiments with the mechanisms of tumor-specific antigens continued, and in the mid-twenti- eth century, Schreiber, Dunn, and Old proved that T cells were capable of providing anti-tumor immune response and surveillance. 5 Later, discoveries included the process of immunoediting (lab growth of cells) and the identifica- tion of a molecular target in cloning the melanoma antigen. INTRODUC TION – THE BODY’S IMMUNE SYSTEM The immune system is made up of white blood cells, organs and tissues of the lymph system – all work together to help the body fight disease and infection. Within the blood- stream, antibodies are blood proteins produced by plasma cells as a response to counteract an antigen (the unique molecule of the pathogen or invader cell). Antibodies or immunoglobulins combine with substances the body sees as foreign (bacteria, viruses). The concept of immunoglob- ulin in the body is to attack the cell’s antigens and mark the cancer cell to be destroyed by immune system cells. Antibodies work in several ways: they signal the immune system and trigger an attack, or they interfere with the cancer cell signal, attempting to grow, divide, and spread. 6 White blood cells (known as T cells) help fight disease, and when the body senses an antigen, it releases T cells as self-defense. The antibody/immunoglobulin also marks a microbe or infected cell to be attacked by the immune system. In some cases, the antibody process may produce macrophages to destroy foreign bacteria or the virus. Sim- ply stated, the immune system is designed to defend the body from disease and infection. Cancer is a complex disease that can outsmart and evade the human immune system. 7 Cancer cells grow and spread because they hide from the body’s immune system. Unfortunately, the immune system often does not recog- nize the cancer invader, and it grows out of control. The hallmark of malignancy is this immune evasion, and this is the reason cancer proliferates. 8 Once cancer cells begin to divide and spread in the body, the inflammatory response dampens the T cell immune response, preventing autoim- munity. Cancer cells in the tumor hijack T cell production to avoid being attacked. Immune Checkpoint Therapy & Monoclonal Antibodies Part of immunotherapy includes the development of thera- peutic antibodies (known as monoclonal antibodies), which are created in the lab. These antibodies are designed to attack specific markers on cancer cells. 9 Part of the mono- clonal antibody process is to mark cancer cells, which helps the immune system identify and destroy them. In addition, monoclonal antibodies may stop cancer cells from divid- ing/growing, or the monoclonal might carry toxins to other cancer cells. This targeted therapy process of monoclonal antibodies occurs when immune system proteins are cre- ated in the lab and then injected into the patient. The overall lab-created process of monoclonal antibodies are meant to interfere with the cancer proliferation by promoting T cell activation; this is also known as Infusion Immune Check- point Inhibitors (ICIs), and it has replaced chemotherapy in some cancer treatment. Immunotherapy or infusion immune checkpoint inhibi- tor (ICI), help the body’s immune system with a mark or target on the cancer cells. This is considered targeted ther- apy, and it makes it easier for the immune process to find and destroy invader cells. The immune system has a dual regulatory system of Cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and programmed cell death protein (PD 1 or PD-L1 created in the lab) in the lymph tissue and tumor environment. 10 The CTLA-4 and PD1/PD-L1 pathways are what help the immune system control cancer growth; the pathways are considered immune checkpoints. Unfortunately, cancer may use these pathways to evade the Immunotherapy or infusion immune check- point inhibitor (ICI), help the body’s immune system with a mark or target on the cancer cells. This is considered targeted therapy, and it makes it easier for the immune process to find and destroy invader cells. | The Surgical Technologist | NOVEMBER 2020 502