The immune system plays a crucial role in identifying and eliminating cancer cells, a process known as cancer immunosurveillance. This involves several key components and mechanisms:Key Components of the Immune System in Cancer Control:T Cells:Cytotoxic T Lymphocytes (CTLs): Recognize and kill cancer cells directly.Helper T Cells: Assist in activating CTLs and B cells.Natural Killer (NK) Cells:Detect and destroy cancer cells without prior sensitization to them.Dendritic Cells:Present antigens from cancer cells to T cells, initiating an immune response.B Cells:Produce antibodies that can bind to cancer cells and mark them for destruction.Mechanisms of Immune Response to Cancer:Immune Surveillance:The immune system constantly monitors the body for abnormal cells and eliminates potential cancer cells before they can proliferate.Antigen Presentation:Cancer cells express abnormal proteins (antigens) on their surface. Dendritic cells process these antigens and present them to T cells.Activation of Immune Cells:T cells are activated upon recognizing cancer-specific antigens, leading to the proliferation and differentiation of CTLs that target cancer cells.Direct Killing:CTLs and NK cells kill cancer cells through mechanisms such as the release of perforin and granzymes, inducing apoptosis (programmed cell death).Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC):Antibodies produced by B cells bind to cancer cells, and NK cells recognize these antibodies, leading to the destruction of the tagged cancer cells.Immune Evasion by Cancer Cells:Cancer cells can develop mechanisms to evade the immune system, including:Immune Checkpoint Proteins:Proteins like PD-L1 on cancer cells interact with PD-1 on T cells to inhibit their activity.Tumor Microenvironment:The environment around the tumor can suppress immune responses through various cells and molecules that inhibit immune activity.Antigen Loss Variants:Some cancer cells may lose or alter their antigens, making them less recognizable to the immune system.Immunotherapy:Immunotherapy aims to enhance the immune system's ability to fight cancer. Types of immunotherapy include:Checkpoint Inhibitors:Drugs that block inhibitory checkpoint proteins (e.g., PD-1/PD-L1 inhibitors, CTLA-4 inhibitors), enabling T cells to attack cancer cells more effectively.CAR-T Cell Therapy:T cells are genetically engineered to express chimeric antigen receptors (CARs) that target specific cancer antigens.Cancer Vaccines:Vaccines that stimulate the immune system to recognize and attack cancer cells.Cytokine Therapy:Use of cytokines (e.g., interleukins, interferons) to boost immune cell activity.Monoclonal Antibodies:Antibodies designed to target specific antigens on cancer cells.

Dear Doctor Saif

Our immune cells are typically very good at recognizing altered or foreign cells and swiftly dispatching them. But in the case of cancer, they seem to behave differently.

In the very early stages of cancer, our immune cells do a good job of killing individual cancer cells. But as time goes on, cancer cells can develop genetic changes that help them escape the immune system. They come up with ingenious ways of bypassing our immune cells and escaping their detection. At this point the immune cells can’t keep up with the evolving tumour. Some cancer cells in the tumour may become too clever and the immune cells can’t adapt fast enough to keep them at bay. Thus, cancer mutates in ways that it evolves to evade the immune system. So, the immune system either gets switched off or suppressed.

As you know that tumors are dysregulated. Tumors like to surround themselves with all kinds of normal healthy cells, which they corrupt and turn into helpers. When a cancer mass is found, you will also find a tumor microenvironment, making it difficult for the immune system to efficiently eliminate cancer cells. Cancer cells can regulate immune cells by upregulating nutrient uptake and metabolite production, and as a result, constructing an immunosuppressive tumor microenvironment that promotes cancer cell growth and immune evasion. Tumor cells also actively induce T-cell tolerance, resulting in an immunoediting process that facilitates tumor re-distribution and growth.

Every person already has an immune system and if we can power the immune system to beat cancer, we will be able to win the battle against cancer. Some advancements in this regard are as follows.

1. Increase the number of immune system cells so that they overwhelm cancer.

2. Change the genetic make-up of the immune cells as this can help the immune system target specific types of cancer.

3. Cancer vaccines are being developed that may teach the immune system to recognize and destroy cancer before it can take hold or come back.

4. Immunotherapy is one of the current advances in cancer care.

I hope with many more such developments we will be able to overcome this challenge.

Best.

The immune system plays a critical role in the body's defense against cancer. Here's how it works and its activities against cancer:

Surveillance: The immune system constantly surveys the body for abnormal cells, including those that may become cancerous. This process is known as immune surveillance.

Recognition: Immune cells, such as T-cells and natural killer (NK) cells, can recognize cancer cells by identifying abnormal proteins (antigens) on their surface.

Attack: Once a cancer cell is recognized, the immune system mounts an attack. Cytotoxic T-cells and NK cells can directly kill cancer cells by releasing toxic substances that cause the cancer cell to undergo apoptosis (programmed cell death).

Activation of Immune Response: Dendritic cells and macrophages can engulf cancer cells and present their antigens on their surface to T-cells, activating a more specific and targeted immune response.

Adaptation and Memory: The immune system can adapt to become more effective at attacking cancer cells over time. Additionally, it can form immunological memory, which allows for a rapid and strong response if the same cancer cells are encountered again.