Cigarette smoking is the leading cause of lung cancer, but only a minority of smokers get the disease. New research suggests why: Some people may have robust mechanisms that ward off lung cancer by limiting genetic mutations.

Researchers at the Albert Einstein College of Medicine say their findings may prove to be an important step in shifting the lung cancer battle from late-stage disease treatment to prevention and early detection.

A long-held assumption in medicine is that smoking triggers genetic mutations in lung cells. Until a few years ago, proving that idea was nearly impossible.

But the researchers at Albert Einstein College developed a new genetic-sequencing technique. It reduces the errors that can lead to inaccurate results, thus giving a true picture of lung cancer’s genetic mutations.

They used the technique to compare the cells lining the lungs in two groups: people up to age 86 who had never smoked and those ages 44 to 81 who smoked at least one pack of cigarettes a day for many years.

Not surprisingly, many more mutations were found in the lung cells of smokers than in the non-smokers. The number of cell mutations also increased proportionally with the amount of smoking — but only to a point. For reasons the researchers don’t fully understand, the most prolific smokers ultimately did not have the highest number of lung cell mutations.

But why is that? The data suggest that some smokers may have a way to suppress the accumulation of further genetic mutations that can lead to lung cancer. Next, the researchers will dig deeper into that question.

Even so, the best advice is the simplest: Just don’t start smoking, or quit if you can.