How Immunotherapy Works to kill cancer cells

Cancer is one of the most challenging diseases affecting millions of people worldwide.
Traditional treatments like chemotherapy and radiation target cancer cells directly, but
they can also harm healthy cells. Immunotherapy, on the other hand, harnesses the body's
immune system to specifically identify and target cancer cells, marking a revolutionary
advancement in cancer treatment.

Understanding the Immune System’s Role

The immune system is a complex network of cells, proteins, and tissues that defends the body
against harmful invaders like bacteria, viruses, and abnormal cells. Normally, immune cells,
particularly T cells, can detect and destroy abnormal cells, including cancerous ones.
However, cancer cells have developed mechanisms to evade immune detection, allowing them to
grow uncontrollably.

How Immunotherapy Works

Immunotherapy enhances the immune system’s ability to recognize and eliminate cancer cells.
This approach works through various mechanisms:

Checkpoint Inhibitors

Cancer cells use immune checkpoints—molecular brakes that prevent an overactive immune
response—to evade detection. Checkpoint inhibitors block these signals, allowing T cells to
attack cancer cells. Common checkpoint inhibitors include:

• PD-1/PD-L1 inhibitors (e.g., Pembrolizumab, Nivolumab) – Block the
  PD-1/PD-L1 interaction to restore T cell activity.


• CTLA-4 inhibitors (e.g., Ipilimumab) – Enhance immune activation by
  blocking CTLA-4, a protein that downregulates T cell function.

CAR-T Cell Therapy

Chimeric Antigen Receptor T-cell (CAR-T) therapy is a groundbreaking treatment where a
patient’s T cells are genetically engineered to recognize and attack specific cancer cells.
These modified T cells are reinfused into the patient, where they multiply and target
cancerous cells effectively. CAR-T therapy has shown promising results in blood cancers like
leukemia and lymphoma.

Cancer Vaccines

Unlike traditional vaccines that prevent infections, cancer vaccines stimulate the immune
system to recognize and attack cancer cells. Examples include:

• Provenge (Sipuleucel-T) – A therapeutic vaccine for prostate cancer.
  


• HPV vaccine – Prevents cervical and other HPV-related cancers by
  targeting the virus that causes them.

Monoclonal Antibodies

These lab-engineered antibodies can directly bind to cancer cells, marking them for
destruction by the immune system. Some monoclonal antibodies, like Rituximab and
Trastuzumab, work by targeting specific proteins on cancer cells, leading to their
elimination.

Cytokine Therapy

Cytokines, such as interleukins and interferons, are signaling proteins that boost immune
response. Drugs like Interleukin-2 (IL-2) and Interferon-alpha enhance the activity of
immune cells to fight cancer.

Advantages of Immunotherapy

• Targeted action: Immunotherapy specifically attacks cancer cells with
  minimal damage to healthy tissues.


• Long-lasting response: The immune system can develop a memory, reducing
  the chances of cancer recurrence.


• Effective against resistant cancers: It provides new hope for patients
  with cancers that don’t respond to traditional treatments.

The Future of Immunotherapy

Immunotherapy has revolutionized cancer treatment, offering new hope for patients with
previously untreatable cancers. However, it's not a magic bullet. Not all patients respond
to immunotherapy, and it can cause side effects. Ongoing research is focused on:

• Identifying biomarkers to predict which patients will benefit from specific
  immunotherapies.


• Developing combination therapies that combine different types of immunotherapy or
  immunotherapy with other cancer treatments.


• Reducing side effects and improving the safety of immunotherapy.


• Expanding the application of immunotherapy to other types of cancer.

Immunotherapy has revolutionized cancer treatment by empowering the body’s own immune system
to fight cancer. As research progresses, we can expect even more effective and targeted
immunotherapies to emerge, offering new hope for cancer patients worldwide.