Genetic flaw causes double trouble.Researchers now believe that a gene they've studied for years may function as a tumor suppressor sup·pres·sor n. 1. or sup·press·er One that suppresses: a suppressor of free speech. 2. A gene that suppresses the phenotypic expression of another gene, especially of a mutant gene. in liver, breast, and other tissues. This gene, which encodes a cell surface protein that binds to growth-inhibiting molecules, is missing in certain cancer cells, report investigators at Duke University Medical Center in Durham, N.C. Tumor suppressor genes tumor suppressor gene n. A gene that suppresses cellular proliferation. When inherited in a mutated state, it is associated with the development of various cancers, including most familial cancers. Also called antioncogene. help prevent a cell from growing and dividing uncontrollably. Like most genes, tumor suppressors come in pairs, and a cell can usually keep the brakes on its growth as long as one copy functions. Delete or mutate mu·tate intr. & tr.v. mu·tat·ed, mu·tat·ing, mu·tates To undergo or cause to undergo mutation. [Latin m both copies, however, and the cell is in trouble. The cell surface receptor encoded by the apparent tumor suppressor gene binds to two different molecules and can suppress cell growth in at least two ways, says Duke's Randy L. Jirtle. First, by attaching to a molecule called transforming growth factor-beta, the receptor sends a strong growth-inhibiting signal to its cell. Second, the receptor deactivates insulin-like growth factor-II, which normally stimulates cell growth. Last year, Jirtle and his colleagues found that in many liver cancer Liver Cancer Definition Liver cancer is a relatively rare form of cancer but has a high mortality rate. Liver cancers can be classified into two types. cells, both copies of the gene for this receptor are either deleted or mutated. "It's like going down the highway with your brakes cut and your foot on the accelerator," says Jirtle. The Duke group, whose results are scheduled for the May Oncogene oncogene Gene that can cause cancer. It is a sequence of DNA that has been altered or mutated from its original form, the proto-oncogene (see mutation). Proto-oncogenes promote the specialization and division of normal cells. , now reports that an absence of the receptor also appears to contribute to breast cancer. In 12 out of 40 breast cancer patients who were missing a copy of the receptor gene, the investigators found mutations in the other copy. Jirtle notes that at least one copy of the receptor gene is often deleted in other cancers, including ovarian cancer ovarian cancer Malignant tumour of the ovaries. Risk factors include early age of first menstruation (before age 12), late onset of menopause (after age 52), absence of pregnancy, presence of specific genetic mutations, use of fertility drugs, and personal history of breast . Jirtle hopes that knowing whether this receptor is missing in a cancer patient will help physicians tailor treatments. For example, promising cancer drugs called monoterpenes bind to the receptor. Patients who lack the receptor may not respond as well to these drugs, says Michael N. Gould of the University of Wisconsin-Madison “University of Wisconsin” redirects here. For other uses, see University of Wisconsin (disambiguation). A public, land-grant institution, UW-Madison offers a wide spectrum of liberal arts studies, professional programs, and student activities. . Gould has recently finished a preliminary clinical trial with one monoterpene, a compound found naturally in lavender oil. In a follow-up study, says Gould, investigators will document the receptor's presence or absence in each cancer patient to determine whether it influences the outcome of the treatment. |
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