Gene Therapy and Cancer
Researchers and scientists are working on new approaches to use gene therapy to cure cancer. Although still under development gene therapy could be used some day to treat and cure many different types of cancer. The technology could be used in a number of different ways.
Stopping the expression of oncogenes. Oncogenes are cancer-promoting genes. They derive from normal genes that have suffered a mutation. An oncogene causes cells to go wild and divide profusely without any control. They can spread to other parts of the body. By inhibiting these oncogenes or their expression, gene therapy could stop cancerous cells in their tracks and mitigate the worst cancer symptoms.
Replacing abnormal or missing genes. Regular cells have tumor suppressing genes to prevent cancer. The gene p53 is one example of such cancer-suppressing genes. A cell with a faulty p53 gene can develop cancer. By using gene therapy techniques a perfectly working p53 gene could be inserted into a patient's DNA to try to bring cells into control. A recent trial (Hoshino, 2008) using gene therapy with p53 genes (and antibiotics) has shown much promise in human esophageal squamous cell carcinoma.
Making tumor cells more “destroyable" by the patient’s immune system. The immune system of a person plays an important role in preventing cancer from developing. However, cancer cells are sometimes able to bypass the patient self-defense system. Gene therapy could be used to insert certain genes that may fortify the patient’s immune system so it will be able to properly find and destroy cancer cells.
Stopping angiogenesis. Angiogenesis, or new blood vessel formation, is essential for tumor development and growth. Gene therapy techniques could add genes to stop this from happening. If blood supply to the tumor is cut, tumors will stop growing or even disappear. A recent review paper (Liu et al. 2006) offers many examples of the use of gene therapy to stop angiogenesis.