Immunotherapy for melanoma works by stimulating the body's immune system to recognize and destroy cancer cells more effectively. Here are the key mechanisms and types of immunotherapy used for treating melanoma:

Mechanisms of Immunotherapy

1. Enhancing Immune Response
   • Checkpoint Inhibitors: These drugs block proteins that inhibit the immune system, allowing T cells to attack melanoma cells more effectively.
   • Types of Checkpoint Inhibitors:
     • CTLA-4 Inhibitors: Ipilimumab (Yervoy) blocks CTLA-4, a protein on T cells that normally helps keep the body's immune responses in check.
     • PD-1 Inhibitors: Pembrolizumab (Keytruda) and nivolumab (Opdivo) block PD-1, a protein on T cells that, when bound to PD-L1 on cancer cells, prevents T cells from killing cancer cells.
   • Sources: American Cancer Society, National Cancer Institute
2. Direct Activation of Immune Cells
   • Interleukin-2 (IL-2): A cytokine that boosts the growth and activity of T cells. High-dose IL-2 can be effective but has significant side effects.
   • Sources: American Cancer Society, Mayo Clinic
3. Oncolytic Virus Therapy
   • Talimogene Laherparepvec (T-VEC): A modified herpes virus that infects and kills melanoma cells. T-VEC also stimulates an immune response against melanoma.
   • Mechanism: The virus is injected directly into the melanoma lesions, causing the cells to burst and release antigens that trigger an immune response.
   • Sources: National Cancer Institute, American Cancer Society

Types of Immunotherapy for Melanoma

1. Checkpoint Inhibitors
   • CTLA-4 Inhibitors
     • Ipilimumab (Yervoy): Blocks CTLA-4, allowing T cells to remain active against melanoma cells. It is often used in combination with PD-1 inhibitors.
   • PD-1 Inhibitors
     • Pembrolizumab (Keytruda)
     • Nivolumab (Opdivo): Both drugs block PD-1, enhancing the immune system's ability to destroy melanoma cells.
   • Sources: American Cancer Society, National Cancer Institute
2. Cytokine Therapy
   • Interleukin-2 (IL-2)
     • Description: Administered to boost the growth and activity of immune cells like T cells and natural killer cells.
     • Usage: Used less frequently due to severe side effects, but can be effective in certain patients.
   • Sources: Mayo Clinic, American Cancer Society
3. Oncolytic Virus Therapy
   • Talimogene Laherparepvec (T-VEC)
     • Description: A genetically modified virus used to infect and kill melanoma cells, also stimulating an immune response.
     • Application: Injected directly into melanoma tumors.
   • Sources: National Cancer Institute, American Cancer Society

Conclusion

Immunotherapy represents a significant advancement in the treatment of melanoma by leveraging the body's immune system to fight cancer more effectively. The main types of immunotherapy include checkpoint inhibitors, cytokine therapy, and oncolytic virus therapy, each working through different mechanisms to enhance the immune response against melanoma cells.

Further Reading

• American Cancer Society: Treating Melanoma Skin Cancer with Immunotherapy
• National Cancer Institute: Immunotherapy for Cancer
• Mayo Clinic: Immunotherapy

These sources provide comprehensive information on how immunotherapy works for melanoma, helping patients and caregivers understand the available treatment options and their mechanisms.