Researches Link Gene to Colon CancerBy Robert Cooke
Discovery of a mutant gene that makes some families highly susceptible to colorectal cancer was announced Wednesday by three research teams, opening the way to early detection and treatment of the dangerous tumors.
"This is the first time a single gene has been linked to a common form of colon cancer," said Dr. Bert Vogelstein, a researcher at the Johns Hopkins University Medical Institutions in Baltimore. "It proves there is a hereditary predisposition for colon cancer."
The discovery makes inherited colorectal cancer the most common genetic disease known. Vogelstein said one in every 200 persons apparently is born with the colorectal tumor gene, meaning scientists are now able to account for up to 13 percent of the 152,000 cases reported annually.
Vogelstein said a diagnostic blood test should be available in two years, leading to early detection and life-saving treatments. Testing will be important because "deaths from colon cancer are totally preventable -- if the cancers are caught early enough," he said.
Dr. Kurt Isselbacher, director of the Cancer Institute at Massachusetts General Hospital in Boston, said people with the mutant gene "are going to have to be monitored fairly closely." Isselbacher, who was not involved in the project, said it also will be important to study large numbers of people to see if everyone who inherits the gene gets colorectal cancer.
The research teams also found evidence linking the same mutant gene to cancer of the uterus, stomach, ovary, small intestine, gall bladder, kidney and ureter. But the gene is not associated with lung or breast cancer.
Vogelstein said the gene itself has not yet been isolated. But its location was traced to a small region of human chromosome 2, where its presence can be detected. The discovery, announced at a news conference in Washington, could help save some of the 57,000 Americans who die each year from the colorectal cancer.
Although it is not yet known exactly what the faulty gene does, the scientists think it helps make copies of other genes during cell division. If it does the job poorly, other genes -- such as those that control growth -- may also be damaged, and cancer can result.
Three detailed reports on the work will appear Friday in the journal Science. Vogelstein's team collaborated with Dr. Albert de la Chapelle and his co-workers at the University of Helsinki in Finland. A third team, headed by Dr. Stephen Thibodeau at the Mayo Clinic in Minnesota, reported similar results.