WASHINGTON — Two groups of scientists working independently have discovered a genetic defect that apparently plays a critical role in the development of numerous kinds of cancer, including tumors of the brain, breast, prostate and kidney.
The defect disables what the researchers believe is a powerful, previously unknown "tumor suppressor" gene that cells use as an emergency brake to halt runaway cancer-causing activity. When such a protective gene is missing, cells are far more likely to become malignant, and their cancers often progress faster.
Thus testing for the gene's absence in a tumor, experts said, might soon help doctors make wrenchingly difficult decisions about which cancer cases require drastic early treatments. Eventually, the findings may also lead to drugs that inhibit the invasive proliferation of cells in a wide variety of cancers.
"I think it's likely that [the gene defect] is going to be involved in a lot of tumor types," said cancer geneticist Ramon Parsons of Columbia University, senior author of a report in today's Science.
Biologist Peter A. Steck of the University of Texas M. D. Anderson Cancer Center, whose group plans to publish its results in the April 15 Nature Genetics journal, speculated the findings could be used in diagnosis within two or three years.
One reason the discovery is important is that researchers around the world are trying desperately to find similar key elements among very different kinds of cancers, and defective tumor suppressors fit that description.
"It's beginning to look like there may be certain common pathways in which [cellular] abnormalities" arise, said Richard S. Kaplan of the National Cancer Institute.
Although there are scores of different tumor types, all cancers arise from abnormally fast-growing clusters of cells that have accumulated genetic errors or mutations. Some of these defects can be inherited; others are caused by exposure to chemicals, radiation, viruses or other agents.