Cancer and genetics are a hard thing to wrap your head around. You see, some cancers have genetic links that increase your risk of getting certain types of cancers. Yet, genetic modifications to your immune system (where genes are modified and re-introduced to your body) show great promise in treating and perhaps curing some cancers.
Cancers linked to family history (genetics)
Cancers that run in families are inherited cancers, also known as germline mutations. When there are germline mutations every cell in a child’s body has a mutation, including reproductive cells (sperm in males, eggs in females). This mutation usually passes from generation to generation. Inherited cancers are a small percentage of all cancer cases, accounting for 5 to 10 percent of all cancers. Just because you have an inherited mutation does not mean you will develop cancer – only that your risk is higher than someone without the inherited gene.
Also, many who believe that there is a single “cancer gene” that determines their cancer likelihood are mistaken. Cancer is a complex disease, and the probability is great that there are genes with many mutations and not a single gene that develops into cancer.
Cancers that are acquired
The most common causes of genetic mutations that cause cancer stem from people damaging genes by their lifestyle or exposure at work. Some examples of acquired genetic cancers include
- Sunlight – skin cancer
- Asbestos – mesothelioma
- Tobacco – lung cancer
- Viruses – cervical cancer
- Age – prostate cancer
Damaged genes cause cancer, healthy genes helps cure cancer
According to Stanford University,
Accordingly, most current research for curing and treating cancer is looking for missing or defective genes that cause cancer or are increasing the risk of you getting cancer. Texas’ world famous MD Anderson Cancer Center cured a patient with lung cancer by fixing a mutated gene (p53). Right now, gene therapies are mostly tested on animals with a small amount of human clinical trials with just small numbers of patients participating.
Why gene therapy?
Researchers have suspected genetic mutation as a contributing cause of cancer for decades. With the completion of the human genome project, researchers have a rich tool to work with on investigating genetic therapies. There are two important reasons why science is following genetics role in cancer treatments so closely.
- Gene-based treatments attack at the molecular level, lessening or eliminating the use of drugs, surgery and radiation.
- Using genetics to identify cancer susceptibility in families or individuals could play a major part in preventing an inherited cancer before it takes place.
How it works
Most gene therapy research explores the replacement of a missing or defective gene with a fully functioning, healthy replica of the damaged gene. This is done by using vectors. Vectors are viruses that do not transmit disease, but do carry the corrected gene to the cells that need it. Viruses are the vector of choice as they can pierce DNA and correct the damage or replace a missing gene. This gene transfer is normally done outside the body, using the patient’s blood or bone marrow and creating the gene in a laboratory. Once the genetic material is grown, it is then introduced into the patient’s genetic material where it penetrates the DNA of cells before reintroducing the new genetic material back into the patient.
Other types of genetic therapy
Gene therapy is more than modifying genes to fight cancer. There are two other ways genetics is used in treating cancer.
- When cancer cells are injected with special genes they make the tumor more susceptible to the workings of anti-cancer drugs.
- Using the multi-drug resistant (MDR) gene into a cancer patient’s bone marrow helps make stem cells less vulnerable to the poisonous side effects of cancer drugs. Stem cells are the makers of blood cells.
Genetics plays the role of villain and savior for many cancer patients. Despite decades of researching genetics and its role in cancer, there are numerous technical, medical and ethical issues surrounding the use of genetic modifications to fight cancer.
Ly Viet Do, M.D. is a graduate of the University of California, Irvine College of Medicine and trained in Radiation Oncology at University of California Irvine City of Hope and Long Beach Memorial. Prior to joining the Cancer Care Institute, Dr. Do was an assistant professor at the University of California, Davis in Radiation Oncology. Dr. Do has presented and lectured at many national and international conferences on brachytherapy, radiosurgery and comparative clinical outcome.
