Treating Cancer with Gene Therapy

The goal of gene therapy is to get at the root cause of a disease. Because genes hold the instructions for making proteins and other building blocks necessary for cell function, if a gene's instructions are incorrect or missing, the "ingredients" for a healthy cell and person may be lacking. Instead of dealing with the errant effects of faulty genes after the fact, gene therapy attempts to deliver the proper instructions to your cells, avoiding the negative affects altogether.

The initial goals of gene therapy were, quite obviously, to address hereditary genetic disorders; diseases specifically tied to our genes. Initially, it was thought that our genes were "fixed blueprints" for our bodies that remained unchanged throughout our life. As it turns out, genes are more complicated and changing than that. The sun, smoking, chemicals and other factors can all damage our DNA and result in mutations that cause faulty genetic behavior. Because of this, many diseases not originally seen as candidates for gene therapy are, indeed, potential targets, including malignant mesothelioma.

Will gene therapy affect a recipient's offspring?

Currently, gene therapy is targeted toward somatic cells (somatic cells include all cells in the body with the exception of sperm or eggs) and do not affect any offspring. In contrast, germ line therapy has the potential to affect sperm and egg cells, and thus the children of recipients.

Mesothelioma is a multifactorial disorder, a disorder that is the result of both inherited genetic mutations and mutations gained through environmental causes. In the case of mesothelioma, the environmental cause is usually exposure to asbestos. Cigarette smoking may compound the likelihood of developing mesothelioma, further revealing the complex nature of mulitfactorial diseases. Along with mesothelioma and other cancers, heart disease and diabetes are also multifactorial disorders. The multiple genetic mutations that cause these multifactorial disorders make them difficult to study and treat.

Combatting cancer with gene therapy is being researched in a variety of ways. Missing or altered genes linked to cancer development may be replaced with functional genes in an effort to prevent cancer.

Another method is to improve a patients immune response to cancer, stimulating the body's natural ability to fend off cancer. This "cancer vaccine," as it's called, is a form of immunotherapy (sometimes called biologic therapy). Clinical trials have already had promising results in fighting non small cell lung cancer and other cancers.

Yet another approach involves making cancer cells more susceptible to the chemotherapy and radiation therapy techniques already in practice. Going a step further than just increasing sensitivity, some researchers are using "suicide genes" to tag cancer cells and then treating the patient with a benign compound or prodrug. The prodrug interacts with the "suicide gene" creating a toxic reaction within the cell, killing it.

Finally, anti-angiogenesis gene therapy involves the introduction of genes that inhibit blood vessel development (angiogenesis) or altering the genes that cause angiogenesis so they are "turned off." Preventing the development of new blood vessels which feed the tumor keeps them from growing much larger than the head of a pin.