Researchers have finally been able to make charges stick against a tumor suppressor gene long suspected. The gene, called NF1 , was identified in 190 as the culprit in neurofibromatosis (NF), a disfiguring and potentially fatal disease that affects one in 3500.
in the number of tomorrow the New England Journal of Medicine , researchers from the University of California, San Francisco, and Roche Biomedical Laboratories report convincing evidence that NF1 gene acts as a suppressor tumor in human cancer. Such genes help regulate cell division, and when they are missing or inactivated by mutations, cell division is unleashed, causing tumors. The discovery suggests that therapies under development that target the pathway of cell division may hold great promise for NF1 patients who develop many non-cancerous tumors and have a very high risk for several types of Cancer.
Scientists already had tons of indirect evidence that NF1 was a tumor suppressor. The disease itself, with its multiple tumors, suggests the work of such a gene has gone wrong. And in a few months NF1 discovery of, the researchers found that its sequence was remarkably similar to a gene called GAP , which was known to regulate the signal system tells a cell to divide. Data from mice also suggested that the gene was necessary to prevent tumor development. But it has been difficult to gather strong evidence needed to confirm the role of tumor suppressor.
The best way to prove that a gene is a tumor suppressor is to show that the gene works properly in normal cells, but is absent or inactive in tumor cells. This has been difficult to prove to NF1 , because the large gene could potentially contain thousands of mutations that render inactive, and it is impossible to screen for all of them. But a tip recently developed to examine the protein product of the gene activated Kevin Shannon, a pediatric hematologist and oncologist at the University of California, San Francisco, and colleagues to gather evidence to load. They examined tissue samples of 18 children with NF who also developed leukemia. In eight patients, the normal cells showed mutated NF1 gene and a normal gene, while cancer cells had only the mutated form. "Overwhelming evidence," said Shannon, the NF1 gene is indeed the culprit in cancers.
Other researchers applaud the work. "This is the best example NF1 is a tumor suppressor, "says David Viskochil, a geneticist at the University of Utah, but he warned that the case is not yet closed: There may be still other genes that play a role in tumor development NF. Nevertheless, he says, the finding suggests that drugs that block the path to cell division will be an effective treatment for NF leukemia related and potentially other disease complications.
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