Immunotherapy fights cancer by harnessing and enhancing the body’s own immune system to recognize, target, and destroy cancer cells. Unlike traditional treatments such as chemotherapy or radiation that directly attack cancer cells, immunotherapy empowers immune cells to identify cancer as a threat and mount a sustained attack against it.
The immune system is naturally designed to protect the body from infections and abnormal cells, including cancer cells. However, cancer cells often develop ways to hide from immune detection or suppress immune responses, effectively putting the immune system “to sleep” around them. Immunotherapy works by removing these disguises or lifting the immune system’s natural brakes, allowing immune cells to see and attack cancer cells more effectively.
One of the main ways immunotherapy works is through **checkpoint inhibitors**. Normally, immune cells called T cells have “checkpoints” — molecules on their surface that act like brakes to prevent them from attacking normal cells and causing autoimmune damage. Cancer cells exploit these checkpoints by producing proteins that bind to these brakes, effectively telling T cells to stand down. Checkpoint inhibitor drugs block these proteins, releasing the brakes and unleashing T cells to attack cancer cells aggressively.
Another approach is **adoptive cell therapy**, such as CAR-T cell therapy, where a patient’s own T cells are collected and genetically engineered in the lab to better recognize cancer cells. These modified cells are then infused back into the patient, where they seek out and kill cancer cells with enhanced precision.
**Cytokine therapy** uses proteins that boost immune signaling to stimulate immune cells broadly, increasing their activity and numbers to fight cancer. Meanwhile, **cancer vaccines** train the immune system to recognize specific markers on tumor cells, priming it to attack those cells when encountered.
The tumor microenvironment—the area immediately surrounding a tumor—is often immunosuppressive, meaning it actively inhibits immune responses. Immunotherapy can alter this environment, reducing suppressive signals and promoting immune cell infiltration and activity within tumors.
However, not all patients respond to immunotherapy. Some tumors develop resistance mechanisms, such as damaging nearby nerves, which triggers inflammatory signals that suppress immune attack. Researchers are also discovering that gut bacteria can influence how well immunotherapy works, with certain bacterial strains enhancing immune responses against tumors.
Immunotherapy can cause side effects because it sometimes overactivates the immune system, leading it to attack healthy tissues. These side effects can include inflammation in organs like the lungs, liver, intestines, or skin, and require careful management.
Overall, immunotherapy represents a revolutionary shift in cancer treatment by turning the immune system into a powerful weapon against cancer. It offers hope especially for cancers that are resistant to conventional therapies, and ongoing research aims to improve its effectiveness and reduce side effects, expanding its benefits to more patients.