Mesothelioma: Immunotherapy & Gene Therapy

Immunotherapy, also referred to as biological therapy, is based on the theory that it is possible to mobilize the body's own immune defenses against cancerous cells. Another name often applies to this therapy, biological response modifiers (BRMs), and is described in this article.
There are several new experimental treatments that try to enhance the immune system's ability to combat malignant mesothelioma. These include gene therapy and the use of cytokine proteins such as interferons and interleukins. These treatments are also being tested in combination with chemotherapy and other treatments.

Gene Therapy:

This a new treatment which is currently in clinical trials. Using an adenovirus for delivery, a "suicide gene" is inserted directly into the tumor. This gene makes the cells sensitive to a normally ineffective drug, such as glanciclovir. Treatment with the drug then destroys those cells that are rapidly dividing - which are the cancer cells - leaving the healthy cells unharmed.

In theory, this approach allows treatment to target the tumor specifically, as opposed to treatments such as chemotherapy which also kill healthy cells.

Gene therapy for mesothelioma is being researched at the University of Pennsylvania, with Dr. Steven Albenda as the principal investigator. This treatment is not without risk, as became apparent in the death of Jesse Gelsinger, a University of Pennsylvania gene therapy trial participant. (Note that Mr. Gelsinger was not a participant in the mesothelioma trial.)

Cytokines - Interferons (IFN) and Interleukins (IL):

Cytokines are small proteins that occur naturally in the human body. They are similar to hormones and have specific effects on the behavior of other cells.

In 1976 Dr. Robert Gallo (later head of the National Cancer Institute, and famous for his work on HIV) isolated a cytokine protein molecule called interleukin-2 (IL2) which is capable of stimulating the growth of immune system cells called T-cells. T-cells are sometimes called "killer cells" because they search out malignant or virally infected cells and kill them. Using IL2 as a treatment for pleural mesothelioma is still in the experimental stages, but researchers hope that injecting IL2 intrapleurally will promote a significant anti-tumor response.