Researchers say phantom gene may increase risk of lung cancer

NEW ORLEANS — A gene that may be carried by one out of 10 people could make them more susceptible to lung cancer, according to a study published this week.

“There’s only a suggestion that this gene exists,” said Joan Bailey-Wilson. “If it does and a person with this gene smoked, the risk of getting lung cancer would be increased tremendously.

“It doesn’t mean a person with this gene would automatically get lung cancer,” Bailey-Wilson said. “It would mean they are much more susceptible to environmental factors.”

The scientists at Louisiana State University Medical Center in New Orleans have yet to confirm the gene’s existence, but their survey of 4,357 people strongly supported their theory the gene exists, Bailey-Wilson said.

“It’s not a wild theory or a guess pulled out of the air,” said the associate professor of biometry and genetics. “At this point, it’s an educated hunch.”

The findings were published in Wednesday’s Journal of the National Cancer Institute.

The LSU research team was investigating why Louisiana’s lung-cancer death rates are among the highest in the nation and why lung cancer appears to cluster in some families.

The findings don’t lessen the role environmental factors, such as smoking, are believed to play, Bailey-Wilson said.

“Lifestyle is still a major factor,” she said. “If the gene is found, it would still mean that 80 percent of the people who get lung cancer do so because of environmental factors.”

The study predicts that most people who get cancer, whether they have the gene or not, are smokers, Bailey-Wilson said. “Gene carriers are more susceptible, but it doesn’t say at all that those who are carriers will get it, or all of those who aren’t won’t get it,” she said.

Among the people interviewed who had lung cancer by the age of 50, 22 percent appeared to carry the gene, Bailey-Wilson said.

The figure dropped to 10 percent among people who developed lung cancer before age 70, she said, but by that time other cancer causers would have had more time to play a part.

Once further research tracks down the gene to its spot on the chromosomes that determine heredity and determines how it works, scientists should be able to develop tests to determine who carries it, said Robert C. Elston, a professor of biometry and genetics who took part in the study.

If the research pans out, physicians would be able to identify people at extremely high risk of developing lung cancer, advise them and monitor them more closely, Bailey-Wilson said.

Success could also lead to more information on cancers and treating them, she said.

Positive identification of the gene is still years away, she said. The researchers are seeking federal funding to continue their work.

The scientists in 1976 began going over autopsies and death certificates in 10 south Louisiana parishes to find lung-cancer victims. They then interviewed the 337 families of victims, and found patterns of lung cancer, said Dr. Henry Rothschild, professor of medicine.

Such clusters of cancer “could be explained on the basis of a gene being passed down,” Elston said.

The scientists have not gone beyond Louisiana to determine how widespread the gene might be, but there is no reason to think the figures would not be about the same nationally, Bailey-Wilson said.

Louisiana has a lung-cancer rate 25 percent higher than the rest of the United States, according to the Louisiana Cancer and Lung Trust Fund.

About 3,000 cases of lung cancer will be diagnosed in Louisiana this year, and 2,700 Louisianians will die of it, the American Cancer Society estimates. Nationally, about 157,000 cases will be diagnosed in 1990, and about 142,000 Americans will die.

Lung cancer is the top killer among men and women, the organization says, with only a 5-percent survival rate.