Gene therapy methods have had an 80% success rate in treating lab rats with brain tumors. Could the same success be duplicated in treating human brain tumors and brain cancer?
Gene therapy is a form of treatment developed to treat diseases that are caused due to genetic malfunctioning. This form of therapy involves modification, addition or deletion of certain specific genes. By introducing specific genetic material into cells, the cells are made to function normally again. Human genetics research and treatment methods may have the key to curing brain tumors.
Most brain tumors usually have a genetic cause, like abnormal or missing genes; brain cancer can also result from genetic abnormalities caused by ionic radiation. Tumors are caused when the abnormal cells replicate indiscriminately and grow in an uncontrolled fashion. This abnormal behavior can spread to other cells and cause tumors in other areas.
Types of Brain Tumors
There are two types of brain tumors - benign and malignant.
Benign brain tumors: These tumors are non-cancerous. Their cells do not replicate and spread to adjoining areas. These tumors are not lethal, unless situated in the crucial areas of the brain; here, they may cause pressure on the brain tissue, leading to death. Examples of benign tumors are Adenoma, Juvenile Pilocytic Astrocytoma and Acoustic Neuroma.
Malignant brain tumors: Malignant tumors are cancerous and their cells do reproduce and spread to adjoining areas. Malignant brain tumors are of two types, primary and secondary.
- The tumors that start in the brain itself are called primary brain tumors.
- Secondary brain tumors are those that spread to the brain through the blood vessels from a primary cancer in another area of the body. There seem to be more incidences of secondary brain tumors than the primary ones.
Some malignant brain tumors are Gemistocytic Astrocytoma, Glioblastoma Multiforme and Medulloblastoma. Survival rates in malignant brain tumors are slim.
The conventional methods of treating brain tumors include chemotherapy and radiation. Now, researchers in human genetics are exploring the treatment possibilities offered by gene therapy.
So how does gene therapy work?
There are several approaches to treating brain tumors with gene therapy. Here are some, briefly -
- Replace damaged or missing genes with healthy, functioning copies.
- Inject genes into cancer cells so they are easily detected and destroyed by the immune system.
- Inject genes that boost the body's ability to fight off cancer cells.
- Inject genes that stop cancer cells from developing new blood vessels. Without regular blood supply, the cancer cells stop multiplying and the tumor stops growing.
- Inject tumor cells with genes that make them vulnerable to chemotherapy and radiation.
- Inject a gene that induces the tumor cells to express an anticancer protein interferon-beta.
Many of these methods have had a 80% positive effect on lab animals. Using them for treating humans is still in the research stage. Patients are carefully screened before selection; most of them have malignant tumors that have not responded to conventional treatments.
Several potential risks still need to be addressed before gene therapy can be taken mainstream -
- The chance of the viral vectors used in gene transfer infecting healthy cells along with the cancer cells.
- Chances of genes getting transferred to the wrong location.
- Chances of transferred genes affecting future generations in a negative way.
The surgery required for injecting the genes into specific brain sections is not without risk either. These risks include hemorrhaging, inflammation and infection.