Researchers find enzyme that protects against lung disease

Israeli researchers said they have identified a naturally produced compound that may explain why only some smokers get lung cancer.

Smokers with low levels of the enzyme were five to 10 times more likely to develop lung cancer than smokers with the highest levels, the team at Israel's Weizmann Institute found.

The enzyme is called OGG1 or 8-oxoguanine DNA glycosylase 1. The enzyme fixes damage done to DNA by smoking and other environmental stresses and is one of a large group of repair compounds in the body.

Writing in the Journal of the National Cancer Institute, Zvi Livneh and colleagues said 40 percent of the 68 lung cancer patients they tested had low levels of OGG1 activity, in contrast to 4 percent of a healthy group of 68 people.

Nonsmokers with the lowest levels of OGG1 also had a higher risk of lung cancer, although their overall risk of cancer was much lower than that of the smokers.

Lung cancer is by far the biggest cancer killer in the world, killing a million people every year worldwide and nearly 160,000 a year in the United States.

Up to 90 percent of all lung cancer patients are smokers, but only 10 percent of heavy smokers develop lung cancer. Smoking is also a major cause of heart disease and stroke.

The researchers said the findings needed to be confirmed in larger studies but they may lead to the development of a blood test that smokers could take to determine their personal risk.