Controversy surrounds the issue of gene therapy due to past misuses and concern about the future of this treatment. Researchers have been studying and reengineering genes to see how they affect disease in animals and some humans. Gene therapy trials help to advance gene therapy as a treatment option for cancer and other diseases, but progress has been slow.
Gene therapy is the process of taking normal genes and replacing, or adding them to a genome that has a defective or altered gene. Two other methods of gene therapy involve repairing the defective gene while on the genome or disabling the gene from operation. Individuals with genetic conditions may have a gene on a chromosome that causes their particular disease or disorder. By replacing the gene or adding a healthy gene to counteract the damaged gene, the disorder or disease should correct itself.
The delivery of the therapeutic gene or DNA is complex and takes much skill. The exact location of the damaged gene must be located and there must be accurate placement of the new gene. This must happen with active cells or the new gene will not have a chance to treat the disease.
The course of delivering the functional gene to its necessary location can happen through a viral or non-viral method. The viral gene therapy method consists of sending a vector (or a genome carrier molecule) that releases the inserted gene to the proper location. This viral method uses viruses such as retrovirus, adenovirus, adeno-associated virus, and herpes simplex virus. The non-viral method consists of going into the target cells and releasing the gene directly or creating an artificial lipid sphere link that takes the gene to the targeted cell.
Due to the complex nature of gene therapy, issues have occurred in gene therapy trials. The FDA does not approve of gene therapy because gene therapy trials thus far have not proven that it's an effective treatment of diseases. So far, there has been one death and two failed gene therapy trials. In 1999, Jesse Gelsinger, 18 years of age, died from multiple organ failures shortly after receiving treatment. In 2002 and 2003, two French children undergoing French gene therapy trials developed leukemia type conditions after their treatment.
The problem with using gene therapy for cancer treatment or the treatment of other disorders is that you don't know how someone's body will react to the new gene. The body may treat it as a foreign object and attack it. Alternatively, the viral method delivery may activate and cause disease or become toxic to the body.
Besides the risks of gene therapy, there are other concerns researchers are looking into:
Many people across the world wait for a cure for cancer. Gene therapy has tried to find this cure.
Much debate surrounds the use of gene therapy, not only because of the risks, but because of the possibility for future misuse. The possibilities of gene therapy are endless, which raises concerns about how far research will go, and whether it will venture into cloning and sperm or egg gene alterations. For now, scientists primarily focus on the treatment and prevention of disease, but no one knows what the future will hold.
Human Genome Project (n.d.) Gene Therapy. Retrieved September 17, 2008, from Human Genome Project Information Web site: http://www.ornl.gov/sci/techresources/Human_Genome/medicine/genetherapy.shtml.
Centre of Genetics Education (n.d.) Gene Therapy. Retrieved September 17, 2008, from Centre of Genetics Education PDF Web site: http://www.genetics.edu.au/.
BBC News (2001). Gene therapy 'prevents cancer'. Retrieved September 17, 2008, from BBC News Web site: http://news.bbc.co.uk/2/hi/health/1191334.stm.
China View (2008). U.S. researchers find gene therapy that kiss pancreatic cancer cells. Retrieved September 17, 2008, from China View Web site: http://news.xinhuanet.com/english/2008-08/06/content_8984414.htm.
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