INTRODUCTION
Biological therapy is the method of treating disease by suppressing or activating the immune system. Some natural therapies stimulate or suppress the immune system to help the body fight cancer, infection, and other conditions. In the case of cancer treatment, biological therapies attack specific cancer cells. Our body’s immune system fights foreign particles, such as germs, in the body.
The immune system should recognize cancer cells in the body as abnormal cells, but it doesn’t need always to do so. Cancer cells can also develop an ability to hide from immune system cells. Or cancer cells can disable or inhibit immune system cells from acting. Biological therapies work in two ways-
- By making the immune system recognize and attack the cancer cells in the body.
- By making cancer cells easier for your immune system to recognize.
Different forms of immunotherapy may be given in different ways-
- Intravenous (IV)- directly into a vein.
- Oral- by pills and capsules.
- Topical- comes in the form of a cream that you rub onto your skin, used in early skin cancer.
- Intravesical- goes directly into the bladder.
TYPES OF BIOLOGICAL TREATMENTS IN CANCER:
- IMMUNOTHERAPY:
Immunotherapy used in cancer treatment helps our immune system to fight against cancer in the body. The immune system helps the body to fight several diseases and pathogens. The immune system comprises white blood cells and organs, and tissues of the lymph system. The immune system detects and destroys the cancer cells and most likely prevents many cancer cells’ growth. The immune cells are sometimes found in and around tumours known as tumour-infiltrating lymphocytes (TILs), a sign that the immune system is acting properly towards the tumour. People whose tumours contain TILs, often do better than people who don’t possess TILs. The cancer cells have several ways to avoid destruction by the immune system by-.
- Cancer cell shows genetic changes that make them difficult to detect by the host immune system.
- Cancer cells have proteins present on their surface that turn immune cells off.
- Cancer cells change the normal cells around the tumour, interfering with how the immune system responds to the cancer cells.
Types of immunotherapy :
Immune checkpoint inhibitors, which are drugs that block immune checkpoints. Immune checkpoints engage when protein on the surface of immune cells called T-cells recognize and bind to proteins on other cells, such as tumour cells. These proteins are known as immune checkpoint proteins. When the checkpoint and proteins bind together, they send an off signal to the T cells of the immune cell and prevent the immune system from destroying cancer. The checkpoints are a traditional part of the system and keep immune responses from being too strong. By blocking them, these drugs allow immune cells to respond more strongly to cancer. The method is approved to treat patients with various cancer types, including breast cancer, bladder cancer, cervical cancer, colon cancer, neck cancer, liver cancer, lung cancer, skin cancer, stomach cancer and rectal cancer.
T-cell transfer therapy is a type of immunotherapy that makes our immune cells better able to attack cancer. The process involves collecting our immune cells, growing these cells in the lab, and then giving the cells back in the body through a needle. This therapy is also called adoptive cell therapy, immune cell therapy and adoptive immunotherapy. The process of growing the T cells in the lab takes 2 to 8 weeks. During this time, you may have treatment with chemotherapy and, maybe, radiation therapy to get rid of other immune cells. Reducing your immune cells helps the transferred T cells to be more effective. The therapy has been studied for the treatment of solid tumours, including breast and brain cancers.
Monoclonal antibodies are system proteins created within the lab. Antibodies in our bodies are produced naturally and also help the immune system recognize factors that cause disease and mark them for destruction. Like the body’s antibodies, monoclonal antibodies recognize specific targets. The monoclonal antibodies keep cancer cells so that the immune system will better recognize and destroy them. Rituximab is an example of monoclonal antibodies, which binds to a protein on B cells and several cancer cells. B cells of immune cells are white blood cells, causing the immune system to kill cancer cells.
Cancer treatment vaccines treat cancer by strengthening the body’s natural defences against cancer. Cancer treatment vaccines are designed to be used in people who already have cancer, unlike cancer prevention vaccines.
They work against cancer cells, not against something that causes cancer. Cancer treatment vaccines are made in three ways-
- They can be made from our tumour cells and causes an immune response that is unique to that cancer type.
- They made from tumour-associated antigens that are found in the specific type of cancer in the patient. The vaccine can cause an immune response in the patient whose cancer produces that antigen. This type of vaccine remains experimental.
- They may be made from patients dendritic cells, which is a type of immune cell. It stimulates the immune system to respond to an antigen on tumour cells. The dendritic cell vaccine has been approved, sipuleucel-T, to treat some men with advanced prostate cancer.
Cancer treatment vaccines can cause flu-like symptoms like fever, chills, weakness, dizziness, fatigue, headache and low or high blood pressure.
Immune-modulating agents are a type of immunotherapy that enhances the body’s immune response against cancer. These agents are used to treat the advanced type of cancer.
2.GENE THERAPY:
The emerging field of cancer gene therapy offers several exciting potential treatments. The term gene therapy encompasses a wide range of treatment types that all use genetic material to modify cells. In lung cancer, doctors use gene therapy to generate cancer vaccines, decrease the blood supply to the tumour, target viruses to cancer cells for lysis and death and introduce genes into the cancer cells that cause death or restore normal cellular phenotype. Newer and safer gene therapy delivery agents are created. Thousands of cancer patients globally have participated in gene therapy trials with remarkably few treatment side effects. Introducing a gene to the tumour will produce proteins that unmask the cells from immune evasion and encourage the development of antitumor antibodies. Vaccines using engineered cells show great promise to treat many cancers that respond poorly to conventional therapy. Other clinical trials demonstrate the potential of unmasking the tumour from immune invasion using immunostimulatory genes inserted directly into the tumour tissue. For example, MDA-7 (IL-24), a cytokine that induces neoplastic cell death, is currently in clinical trials for its ability to cause a systemic immune response in melanoma patients. Oncolytic gene therapy vectors are generally viruses that have been genetically engineered to target and destroy cancer cells while remaining innocuous to the rest of the body. Oncolytic vectors are designed to infect cancer cells and induce cell death by propagating the virus, expression of cytotoxic proteins and cell lysis. In colon cancer and bladder cancer have shown survival benefits and reduced metastasis using oncolytic viral agents.
This one of the most exciting treatments to emerge from the concept of gene therapy is that gene transfer or insertion involves the introduction of a foreign gene into the cancer cell or surrounding tissue. Genes with several different functions have been proposed for this type of therapy, including suicide genes (genes that cause cellular death when expressed), antiangiogenesis genes and cellular stasis genes. Gene transfer technology for cancer treatment holds great promise for increasing the effectiveness of current chemotherapeutic treatment regimens.
