Breast cancer remains one of the most common cancers affecting women worldwide. While traditional treatments such as surgery, radiation, and chemotherapy have improved survival rates, there's a growing interest in harnessing the body's immune system to fight cancer. This approach, known as immunotherapy, is revolutionising cancer treatment, offering new hope for patients. In this blog, we will explore the relationship between breast cancer and the immune system and delve into how immunotherapy works.
The Immune System and Cancer
The immune system is the body's defence mechanism against infections and diseases, including cancer. It comprises various cells and proteins that detect and destroy abnormal cells. However, cancer cells often evade immune detection by exploiting certain mechanisms. For example, they can produce proteins that suppress immune responses or create an environment that inhibits immune activity.
In the case of breast cancer, the immune system's ability to recognize and attack cancer cells is often impaired. Tumours can grow unchecked because the immune system either fails to detect them or is too weak to mount an effective response. This is where immunotherapy comes into play, aiming to enhance or restore the immune system's ability to fight cancer.
What is Immunotherapy?
Immunotherapy is a type of cancer treatment that utilises the body's immune system to target and destroy cancer cells. Unlike traditional therapies that directly attack cancer, immunotherapy empowers the immune system to do the work. This approach has shown promise in treating various cancers, including breast cancer.
Types of Immunotherapy for Breast Cancer
There are several types of immunotherapy used in breast cancer treatment:
Checkpoint Inhibitors:
These drugs block proteins that prevent immune cells from attacking cancer cells. Examples include pembrolizumab and atezolizumab, which target the PD-1/PD-L1 pathway, enhancing the immune response against cancer cells.
Adoptive Cell Therapy:
This involves collecting and using the patient's immune cells to treat their cancer. T-cells are extracted, modified to enhance their cancer-fighting abilities, and then infused back into the patient.
Monoclonal Antibodies:
These laboratory-made molecules can target specific antigens on cancer cells, marking them for destruction by the immune system. Trastuzumab (Herceptin) is a well-known monoclonal antibody used in breast cancer treatment.
How Immunotherapy Works
Immunotherapy works by either stimulating the immune system to work harder or smarter to attack cancer cells or by providing it with components, such as man-made immune system proteins, to enhance its ability to fight cancer. Here's a closer look at how different types of immunotherapy work:
Checkpoint Inhibitors and Adoptive Cell Therapy
Checkpoint inhibitors release the "brakes" on the immune system, allowing it to attack cancer cells more effectively. Tumours often use checkpoint proteins like PD-L1 to protect themselves from immune attack.
By blocking these checkpoints, drugs like pembrolizumab enable immune cells to recognize and kill cancer cells. In adoptive cell therapy, T-cells are removed from the patient's blood and genetically modified to enhance their ability to target cancer cells. These engineered T-cells are then expanded in the lab and reintroduced into the patient, where they seek out and destroy cancer cells.
Monoclonal Antibodies
Monoclonal antibodies bind to specific proteins on cancer cells, marking them for destruction by the immune system. Some antibodies can also deliver toxins directly to cancer cells, killing them while sparing healthy cells.
The Future of Immunotherapy in Breast Cancer
Immunotherapy is a rapidly evolving field, and ongoing research is uncovering new ways to enhance its effectiveness. Combination therapies, which use immunotherapy alongside traditional treatments, are showing promise in improving outcomes. Additionally, identifying biomarkers that predict response to immunotherapy can help tailor treatments to individual patients, maximising benefits while minimising side effects.
Dr. Pragati Singhal
