Harnessing the Immune System to Fight off Cancer - Immunotherapy

A well-functioning immune system would deploy T-cells to keep the body healthy and free from foreign cells either in form of a mutated cell or pathogen. T-cells would move around the body inspecting body cells to determine if they are normal or healthy. T-cells have proteins called receptors on their surfaces and are used to exchange signals with the body cells to detect if they are foreign or malfunctioned and need to be eliminated.

Cancers are known to be the second leading cause of death worldwide. Cancerous cells are usually difficult to keep in check as they often override the defensive mechanisms of the body's immune system. The immune system sometimes have this difficulty, either because it doesn't recognize the cancer cells as foreign or there isn't a strong enough immune presence to overtake cancer cells' rapid growth.

The persistence of cancerous cells is caused by the production of proteins either by the cancer cells or the immune cells itself to prevent the T-cells or immune system from attacking the cells.

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Immunotherapy; Immune Checkpoint Inhibitors

Scientists now rely on Immunotherapy, a technique that harnesses the immune system to fight off cancer cells, and major dicovery has been made in this technique - the proteins that prevent the T-cells from attacking cancer cells (checkpoints).

The checkpoint functions to effectively inhibit the immune system through various mechanisms. The first of such molecules shown to inhibit both T-cell proliferation and production was cytotoxic T-lymphocyte associated protein 4 (CTLA-4). Other immune checkpoints discovered was that of the transmembrane programmed cell death-1 (PD-1) T-cell receptor and its ligand, programmed death-ligand 1 (PD-L1) which interact together and send deceptive signals to the immune system that they are not harmful.
With this discovery, efforts turned to blocking this inhibitory pathway in an attempt to activate dormant T-cells directed at cancer cells. This lead to the formulation of Immune Checkpoint Inhibitors.

Immune Checkpoint Inhibitors are drugs that inhibit the production of checkpoint that helps cancer cells to evade destruction by T-cells. The drugs have proven to be efficient and has been used in treating cancers of the skin, lymph and lung.

Although some side effects are involved, some patients have seen their cancer degenerate from stage 4 to undetectable.

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Other drugs and therapies used in Immunotherapy includes:

• Cancer vaccines
• Personalized cell therapy
• Bone marrow immune cell therapy

References:

1. https://www.hopkinsmedicine.org/kimmel_cancer_center/centers/bloomberg_kimmel_institute_for_cancer_immunotherapy/about_cancer_immunotherapy/index.html
2. https://www.cancercenter.com/treatment-options/precision-medicine/immunotherapy/checkpoint-inhibitors
3. https://www.cancerresearchuk.org/about-cancer/cancer-in-general/treatment/immunotherapy/types/checkpoint-inhibitors
4. https://www.ncbi.nlm.nih.gov/m/pubmed/26282545/
5. https://amp.cancer.org/treatment/treatments-and-side-effects/treatment-types/immunotherapy/immune-checkpoint-inhibitors.html