Gene Therapy Essay, Research Paper
Cancer is diagnosed in almost 1.5 million people in the United States annually. Approximately one-half million Americans die of cancer annually, making it the second leading cause of death in the U.S. Cystic fibrosis is an inherited, fatal disease occurring once in every 2,500 Caucasian births and once in every 17,000 African American births. Genetic research has failed, so far, to solve many genetic-based cancers, but it has identified the gene and its location (on chromosome 7) responsible for cystic fibrosis (Encarta ?98 ?Cancer (medicine)?, ?Cystic fibrosis?). Many researchers and lay people object to genetic research and its application, genetic engineering, fearing a genetic accident comparable to the killer bee incident in South America. The promise of genetic research in the form of gene therapy is, however, overwhelmingly beneficial to people with genetically passed diseases, like cystic fibrosis. Research and testing for gene therapy must be funded and continued.
One common form of gene therapy is recombinant DNA. Recombinant DNA is defined as a novel DNA sequence produced by artificially joining pieces of DNA from different organisms together in the laboratory. Therefore, recombinant DNA is DNA that could cure a host body when it is combined with the DNA of a pathogen. The recombined pathogen is reinserted into the host where the genetically improved DNA is absorbed by the host (Genethics: The clash between the new genetics and human values 348). The hope is for successful treatment of the malady. In opposition to continued gene therapy research, critics of recombinant DNA fear that the pathogenic, or disease-producing, organisms used in some recombinant DNA experiments might develop extremely infectious forms that could cause cancer or other diseases. In an effort to prevent such an occurrence, the National Institutes of Health (NIH) has established regulations restricting the types of recombinant DNA experiments that can be performed using common pathogens (Encarta ?98 ?Genetic Engineering?). Scientists have limited gene therapy to somatic cell gene therapy. In the case of any experimental treatment, therapy is limited to terminally ill patients. Because of these restrictions and procedures, the risk of developing a form of cancer or other diseases is limited. It is further restricted to the individual patient. Somatic therapy uses cells that are not naturally reproductive. Somatic therapy ?is the ethical equivalent of an organ transplant operation ? a local transformation in a patient?s phenotype, without a corresponding change in the underlying genotype of his or her reproductive cells.?(Genethics: The clash between the new genetics and human values 183) Germ therapy does use cells that are reproductive in nature. Scientists have stayed away from germ therapy, indicating the recognition of profound biological differences between somatic and germ cells in the human body.
Despite scientists? avoidance of germ therapy, ethical issues also prove problematic. One ethical dilemma to genetic research is the possibility of introducing undesirable genetic mutations into the human species should research be focused on germ cell mutations. The random trajectories of transplanted genes can land themselves in the middle of an existing gene, breaking the continuity of its linear DNA sequence. To date, however, genetic changes have resulted in recessive rather than dominant mutations. There is, therefore, no health hazard to the modified somatic cells. Unlike somatic cells, whose genetic cha
Despite many restrictions on the kinds of research available to geneticists, some genetic diseases, such as cystic fibrosis, have had their genetic locations identified (chromosome 7). In some cases, locating the afflicting chromosome leads researchers closer to discovering cures. Certainly, knowing the location limits the scope of the research. Trials are currently underway using recombinant human enzyme DNAse to liquefy the thick mucus that causes death in childhood or early adulthood by cystic fibrosis. The promise of genetic research is to move beyond identifying locations to find causes and, ultimately, cures for major diseases.
In addition, gene therapy may some day prove useful in the treatment and curing of such common disorders as cancer, AIDS, and the common cold. These are diseases that are not inherited. Gene insertion can program a cell for an entirely new function. Gene therapy research is currently underway to treat cancer. It involves inserting into a tumor a type of gene that tells cells to stop dividing or commit suicide. Early results show some success. Tumor growth has been halted or even reversed. Some experiments are combining gene therapy with radiation therapy. The genes are inserted into the tumors, but don?t function until they are exposed to radiation. Additional research involves a virus known as adenovirus. The genes of the virus are combined with a gene used for cancer treatment. The virus is then exposed to the body, delivering the new genetic code to all cells including the cancer cells it?s targeted to treat. Yet another experiment with adenovirus involves the removal of a specific gene that allows the virus to reproduce in normal cells. The virus is exposed to the body, but because of the missing gene, the virus does not affect normal cells. When it enters the cancer cells, it is allowed to multiply and eventually kill the cancer cells. Efforts are even being made to create a cancer vaccine. Researchers are also attempting to fight AIDS by using gene therapy to make cells resistant to the virus (Encarta ?98 ?Gene therapy?). Cures for viruses could prove to be the most important use for gene therapy. If a cure for viruses was discovered, half of the world?s health problems would be solved.
Genetic engineering and gene therapy research should be continued, even at the expense of many other areas of medical study. Gene therapy provides the most likely prospect the human race has to discover treatments and cures to the most common, yet deadly of diseases such as cancer and AIDS. Scientists have a long way to go to finish the mapping of the human genome, but rapid progress is being made. The possibilities are exciting. Genetic engineering is currently a fledgling science that will continue to grow as technological advances allow scientists to see more and more of our genetic code up close.
Gene Therapy
Nick Bostic
Mrs. Day
AP II
10/13/97
?As regards ethics, what is important is to realize the new dangers and to consider what ethical outlook will do most to diminish them.?
-Bertrand Russell,
In The Science to Save Us from Science