Cancer Immunotherapy

Cancer Immunotherapy

Cancer immunotherapy harnesses the body's immune system to combat cancer. The fundamental idea is to stimulate the patient's immune response to target and destroy malignant tumor cells. This can be achieved through various methods, such as immunization with a cancer vaccine like Dendreon's Provenge, where the patient's immune system is trained to recognize and eliminate tumor cells.

Alternatively, therapeutic antibodies can be administered to activate the patient's immune system in targeting and destroying tumor cells. Another approach is cell-based immunotherapy, which involves utilizing immune cells like Natural Killer Cells (NK cells), Lymphokine Activated Killer Cells (LAK), Cytotoxic T Lymphocytes (CTLs), and Dendritic Cells (DC).

These cells can be activated in vivo by certain cytokines or isolated, enriched, and infused back into the patient to fight cancer. However, since the immune system distinguishes between self and non-self, many tumor cells may go unnoticed by the patient's immune system because they are essentially the patient's own cells that have proliferated uncontrollably.

Despite this, some tumor cells exhibit abnormal antigens that are either inappropriate for their cell type or environment, or are typically only present during embryonic development (e.g., fetal antigens). For instance, the glycosphingolipid GD2 is expressed on the surfaces of various tumor cells, including neuroblastoma, medulloblastomas, melanomas, and others. GD2 becomes a target for immunotherapies due to its presence on tumor cells but limited exposure to the immune system under normal conditions.

Furthermore, certain tumor cells express cell surface receptors that are rare or absent on healthy cells, leading to uncontrolled cell growth. For example, ErbB2, an overactive cell surface receptor, is abundant on the surface of breast cancer tumor cells.

It's important to note that some agents used in immunotherapy may trigger the reactivation of latent tuberculosis (TB), necessitating evaluation before therapeutic use.