How Does Gene Therapy Work?
In most gene therapy studies, a "normal" gene is inserted into the genome to replace an "abnormal," disease-causing gene. In cancer, some cells become diseased because certain genes have been permanently turned off. Using gene therapy, mutated genes that cause disease could be turned off so that they no longer promote disease, or healthy genes that help prevent disease could be turned on so that they can inhibit the disease.
Other cells may be missing certain genes. Researchers hope that replacing missing or defective genes can help treat certain diseases. For example, a common tumor suppressor gene called p53 normally prevents tumor growth in your body. Several types of cancer have been linked to a missing or inactive p53 gene. If doctors could replace p53 where it's missing, that might trigger the cancer cells to die.
How are the genes delivered into cells?
A carrier molecule called a vector must be used to deliver the therapeutic gene to the patient's target cells.
1. Viruses
The most common gene therapy vectors are viruses because they can recognize certain cells and carry genetic material into the cells' genes. Researchers are trying to take advantage of this unique capability. They:
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| Image courtesy of the National Library of Medicine | |
- Remove the original diseasecausing genes from the viruses,
- Then replace them with the genes needed to stop disease
- Then insert the altered viruses into a person's diseased cells to deliver their genetic material.
