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Cancer Genetics
During the course of the past 25 years, scientists have learned that changes, or mutations, in genes play key roles in the growth and behavior of cells. These changes trigger abnormal processes inside cells that can take years or decades to cause cancer. As scientists begin to understand the genes and abnormal processes involved in cancer, they will learn where exactly in the cell to direct treatments that halt the events leading to the disease. Cancer results from alterations in a small number of the 100,000 genes in the human body. The mysteries of cancer are wrapped up in the essential nature of life, the ability to copy and transmit genetic information written in a molecule called DNA that makes up the body's genes. Scientists know how to find that information and are learning how to read it. This new understanding will lead to new approaches to diagnosis and treatment, based on the nature of each cancer what caused it, how it grows, and what treatments will halt its growth.
Advances Over the past 25 years, scientists have discovered the first human genes linked to cancer. These include classes of genes called oncogenes and tumor suppressor genes, and genes involved in the repair of damageto other genes. Researchers already have found more than 20 genes linked to cancers that run in families. Many more are expected to be located in the near future. The Human Genome Project is now closing in on a full-sequence map of human DNA. Like a telephone book, the map will contain the names and addresses of all 100,000 genes and considerably simplify the search for cancer genes in the years to come. Research has yielded the first gene tests for people with certain cancers in their families. With tests now available, many people can choose to find out whether or not they have inherited a mutation in a gene that increases their risk for a certain type of cancer.
Opportunities Cancer Genes. With the great progress in genetics, researchers have now begun to search for all the altered genes involved in cancer. Diagnostics. In tandem with the search for all cancer genes, efforts are under way to develop powerful new tools that will look for abnormal patterns of activities in the genes, proteins, or protein networks that drive the development of cancer. These clues will tell doctors whether a tumor will grow fast or slow and whether it will spread. Risk. Work is being done to improve gene tests, making them more reliable in predicting whether someone has an altered gene and is at increased risk of getting cancer. Research also is ongoing to explore the social, legal, and ethical issues arising from gene tests.
Additional Reading "Evolutions: Cancer Genes." The Journal of NIH Research, January 1992. Weinberg, R. "How Cancer Arises." Scientific American, September 1996. Understanding Gene Testing. National Cancer Institute, NIH Publication No. 96-3905, 1996.
Statistics are from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) database (January 1997) and from the American Cancer Society's Cancer Facts and Figures1997, which contains estimates based on SEER data. The Cancer Information Service provides a nationwide telephone service for cancer patients, and their families, the public, and health care professionals. The toll-free number is 1-800-4-CANCER (1-800-422-6237); services are provided in English and Spanish. People with TTY equipment may call 1-800-332-8615. |
