Introduction
Introduction
Cancer causes 7 million deaths per year or 12.5% of total deaths in the world. Today with advances in surgery, chemotherapy and radiation therapy, cancer mortality has been reduced. However as the average lifespan of human beings increases so too has the incidence of cancer especially in the elderly. It is believed that any person who lives long enough will eventually get cancer.
Surgery, radiotherapy and chemotherapy are the three mainstays of cancer treatment. Now we can consider a fourth dimension - immunotherapy, which harnesses our immune system's innate and adaptive ability to combat diseases.
Our immune system protects us against invasion by microorganisms. Scientists have come to realize that the immune system also plays a crucial role in preventing cancer. The implication of this finding is that, by designing cancer vaccines, it is possible to boost the immune system to enable it to combat cancer more effectively.
Traditional preventive vaccines have successfully prevented infectious diseases like small pox, polio and influenza. Recently, great progress has been made in the development of vaccines for the prevention of cervical cancer, caused by human papilloma virus. Now it is even possible to create therapeutic vaccines against cancer, such as Dr Hasumi's HITV (Hasumi™ Immuno-Therapeutic Vaccine), which is used for treating cancers in patients already afflicted and not for preventing cancers.
What is Cancer Immunotherapy
Cancer Immunotherapy is the use of the immune system to reject cancer. The main premise is stimulating the patient's immune system to attack the malignant tumour cells that are responsible for the disease. The human immune system can be divided into two branches; both are involved in fighting cancer.
Innate : Barriers that human beings are born with, including special cells, to fight specific bacteria and other invaders. Natural killer cells are the most significant innate cells that fight cancer directly.
Adaptive : Response that the immune system generates to fight threats as they occur. Lymphocytes are cells involved in fighting these threats. There are two types of lymphocytes, B cells and T cells. Some lymphocytes are cells that trigger immunity, while other lymphocytes are memory cells that allow this adaptive response to occur repeatedly. Cytotoxic T cells are the adaptive cells that directly fight cancer. However, they cannot always recognize cancers and need antigen-presenting cells, dendritic cells, to help them do so.
Properties of Tumors
• Since they resemble normal cells, tumors tend not to trigger the immune system.
• Tumors also actively evade the immune system in different ways.
• Immune cells are not very efficient in detecting tumor growth.
Cancer Vaccines
• Vaccines boost the immune system.
• Preventive vaccines may be used to prevent cancers induced by viruses, such as cervical cancer.
• Most cancer vaccines will probably be therapeutic, used for patients who already have cancer.
• Cancer vaccines modify the immune system response to evoke a strong and specific immune response.
• Types of cancer vaccines include :
- Tumor antigens used to familiarize the body against the cancer
- Monoclonal antibodies to mimic tumor antigens
- Stimulation of the cytotoxic T cells to fight the cancer
