Test may help smokers assess lung cancer risk

SCIENTISTS believe they may soon be able to develop a blood test for smokers to determine if they will contract lung cancer in later years.

Israeli scientists have discovered a natural enzyme called OGG which may help explain why some smokers develop lung cancer and others do not.

Smokers with low levels of the enzyme were five to 10 times more likely to develop lung cancer than smokers with the highest levels.

Their findings, published in the Journal of the National Cancer Institute, suggest that some people are genetically predisposed to developing lung cancer.

Lung cancer kills one million people worldwide each year, including 7,000 Irish people. In nine out of 10 cases, it is caused by smoking and passive smoking.

The Weizmann Institute of Science looked at the activity of the OGG enzyme in blood samples of 68 patients with lung cancer and 68 healthy people. Some 40% of the lung cancer patients had low levels of OGG activity, in contrast to 4% of a healthy group.

Non-smokers with the lowest levels of OGG also had a higher risk of lung cancer, although their overall risk of cancer was much lower than that of the smokers.

The Weizmann Institute said a substantial fraction of lung cancer cases might be caused by a combination of smoking and reduced OGG activity.

“If so, then screening for smokers with low OGG activity, followed by smoking cessation in these individuals, may lead to a decrease in the incidence of lung cancer,” the researchers said.

The scientists said they would have to test their enzyme theory on a larger sample and they could foresee a blood test being developed for smokers to see if they were genetically predisposed to lung cancer.

However, Action on Smoking and Health (ASH) Ireland said even smokers with high levels of the OGG enzyme should be wary.

“While the enzyme may protect against lung cancer, it wouldn’t protect against heart disease and all the other cancers that smoking causes. If you’re not caught by the lung cancer, the smoking will get you in the end, one way or the other,” said spokesman Fintan Howell.

The Roy Castle Lung Foundation in Britain said it feared the research would have little impact on smokers. “When this blood test is available, people will be able to find out whether they are susceptible to lung cancer, but smokers already know that they are at risk of dying from smoking-related diseases and it doesn’t stop them. They think they are infallible,” said chief executive Mike Unger.