Gene Therapy

Gene therapy is a technique for correcting defective genes that are responsible for disease. Gene therapy can utilize various approaches to accomplish this, but most often it involves replacing a defective gene with a copy of a healthy gene, so that an individual's malfunctioning cells, tissues and organs can work properly (1, 2).

Genes carry the blueprint that instructs cells to produce specific proteins. When genes are damaged and the proteins are unable to carry out their normal functions, it can result in disorders such as cancer. By inserting healthy instructions in the form of genetic material (DNA and RNA) into cells, gene therapy may be able to treat these conditions (1, 3).

In most gene therapy studies currently underway, a normal gene is inserted into the patient's cells to replace an abnormal, disease-causing gene. A carrier molecule, called a vector, is used to deliver the therapeutic gene to the cells being targeted (e.g., lung cells in the case of lung cancer). Most often these vectors take the form of viruses, as they have the ability to delivery genes to human cells. The viruses are manipulated so that instead of delivering harmful genetic material (such as in the instance of the flu or chicken pox), they deliver healthy human DNA to replace the recipient's abnormal gene. Ideally, the therapeutic gene transmits the blueprint for generating the proper proteins, and the targeted cells restore themselves to a healthy state (1, 2).

Though this vector virus model is the most common avenue of research, there are other methods of delivering healthy genes to replace defective genes, each with their own potential and pitfalls. More research is needed in this area, just as it is needed in entirely different approaches to gene therapy (e.g., replacing healthy genes with abnormal genes to combat disease). Currently, gene therapy is being studied in clinical trials for a variety of cancer types, but in the U.S. it is not currently available outside of clinical trials (1, 2, 4).

'Gene Therapy' Sources:
  1. "Gene Therapy for Cancer: Questions and Answers." From the National Cancer Institute's website. Available: http://www.cancer.gov/cancertopics/factsheet/Therapy/gene (Accessed July 31, 2007).
  2. "What is Gene Therapy?" From the website of the University of Utah Genetic Science Learning Center. Available: http://gslc.genetics.utah.edu/units/genetherapy/whatisgt/ (Accessed July 31, 2007).
  3. "Detailed Guide: What Is Cancer?" From the American Cancer Society website. Available: http://www.cancer.org/docroot/CRI/content/CRI_2_4_1x_What_Is_Cancer.asp?sitearea= (Accessed July 31, 2007).
  4. Peel, David, MBChB. (2007) "Virus Vectors & Gene Therapy: Problems, Promises & Prospects." Special Study Module Project Report, Department of Microbiology & Immunology, University of Leicester. Available: http://www.tulane.edu/~dmsander/WWW/335/peel/peel1.html (Accessed July 31, 2007).

 
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