Immunotherapy offers new hope in the fight against cancer

Immunotherapy offers new hope in the fight against cancer

The fight against cancer seems to be moving more recently to immunotherapy. Stanford University Medical Center researchers are confident that the immune response is the key to eradicate cancer and now they trying to find ways to destroy malignant tumors.

Our immune system’s ability to fight microorganisms lies on the capacity to differentiate the body’s own cells ( self) from the foreign ones ( non-self). Normally the immune system does not react against the body’s own cells, a phenomenon called immune tolerance. Trying to kill cancer cells by immune system cells is quite difficult since the tumor cells are simply cells in the body that made bad choices regarding growth and proliferation. Often even if the initial cancer cells are destroyed by the immune system, then it happens that certain immune cells called regulatory T cells, or Tregs,  recognize cancer cells as self and stop their destruction.

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But now researchers have made progress and found that the initial immune response against cancer may be more persistent. Experiments on animals made by Ronald Levy, MD, professor of oncology at the School of Medicine and pioneer in the field of cancer immunotherapy, and Postdoctoral Scholar Aurelien Marabel, MD, showed that anti-cancer immune response may be more persistent. This is possible by blocking Tregs by antibodies  injected directly into the tumor. Levy said that these monoclonal antibodies target and destroy these regulatory T cells related to tumor.

Levy and his team of researchers implanted human lymphoma cells under the skin of rats  or injected the cells directly into the bloodstream. Then after cancer appearred , rats were treated with a combination of two highly specific monoclonal antibodies that were linked to regulatory T cells. It should be noted that some of the anti-Treg antibodies are already used in cancer therapy, such as ipilimumab which is used in the treatment of metastatic melanoma. However there are side effects for these anti-Treg antibodies because they are injected in large doses into the blood and inhibits not only tumor cells but also the rest of the cells in the body.

However, Levy and his team used much lower doses to be injected directly into the tumor so that adverse effects would not occur. They believe that by injecting antibodies into the tumor, the immune system from all over the body is activated to fight the cancer. It was found that the triple of therapy: two anti-Tregs antibodies plus the injection of a molecules that activate the anti-cancer immune response, was very effective in rats with distant metastases. Levy said that the study results could change the way we use the immune system to fight cancer.