News that some people may be born with an elevated risk of lung cancer raises almost as many questions as it answers about one of America's biggest public health issues.

QUESTION: Does this mean people can find out now if they have a gene that will cause lung cancer?

ANSWER: Not right away. No commercially available genetic screening test exists. Creating such a test will be one of the early goals once specific lung cancer genes are identified.

Q: What does this finding mean to people who have lung cancer now?

A: It won't change how people get treatment, until new drugs are developed, which remains years away.

Q: If lung cancer runs in the family, what should relatives do?

A: In cases where at least two cases of lung cancer have occurred among blood relatives, it could increase pressure on family members to stop smoking, to get genetic screening once available, and to consider getting chest CT scans that can detect early signs of lung cancer.

Q: If people have the lung cancer gene, will they lose their health insurance?

A: This remains a fuzzy area. A federal law passed in 1996 prohibits group health plans from using genetic information to deny coverage, if a person does not currently have a disease. In 1995, the definition of "disabled" in the Americans with Disabilities Act was expanded to include people who carry disease-linked genes. Several states also have laws against genetic discrimination. These protections remains largely untested in the courts.

Q: Is it safe to smoke for people who don't have the gene?

A: Absolutely not, doctors say. As many as one in six heavy smokers will develop lung cancer later in life. Only some of them will have the gene. Beyond lung cancer, smoking also can cause heart disease, emphysema and other forms of cancer.

Q: What will researchers do with this finding?

A: The first step will be to hunt more closely among the 50 most likely targets for the gene or genes that are linked to lung cancer risk. From there, efforts can start to develop a genetic screening test and more focused treatments for lung cancer.

Q: How many people have the lung cancer gene?

A: No one knows. But experts speculate that the gene will be about as common as the BRCA-1 and BRCA-2 genes linked to breast cancer, which were identified in 1994. They account for an estimated 5 percent to 10 percent of cases.

Q: Does the gene occur more often in men or women or in various races and ethnic groups?

A: No one knows. For example, of the 52 families in this study, only two were African-American. But once a gene is identified, it becomes possible to do larger population studies.

Q: What is a CT scan and should smokers get them?

A: Spiral or helical CT scanners are high-tech X-ray machines that create a 3-D image of a person's lungs in about 15 seconds by taking a series of "slices" as the rotating device passes over the patient. Some medical groups already sell this service at prices ranging up to a few hundred dollars. Experts disagree over whether these tests are effective, and critics remain concerned that the scans generate too many false positive results. A nationwide study of 50,000 people who got the scans, funded by the National Institutes of Health, plans to follow cancer patients detected by the tests for several years to see if early treatment actually improves survival rates.

Tim Bonfield