Scientists Find Cancer Culprits in Cigarette Smoke

Hydrogen peroxide and other oxidants cause lung cells to become malignant

THURSDAY, Feb. 28 (HealthDay News) -- It's long been known that smoking causes lung cancer, but a new study is the first to show that the hydrogen peroxide in cigarette smoke is what actually causes healthy lung cells to turn cancerous.

Researchers from the University of California, Davis, said their findings may help lead to new treatments for lung cancer and may help the tobacco industry develop "safer" cigarettes by eliminating such substances in the smoke.

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"With the five-year survival rate for people with lung cancer at a dismally low 15.5 percent, we hope this study will provide better insight into the identification of new therapeutic targets," senior author Tzipora Goldkorn said in a prepared statement.

In this laboratory study, the researchers exposed different sets of human lung cells to cigarette smoke or hydrogen peroxide and then incubated the cells for one to two days. The cells were then compared to unexposed airway cells. The cells exposed to cigarette smoke and those exposed to hydrogen peroxide showed the same molecular signatures of cancer development. The unexposed cells showed no such changes.

The findings are published in the March issue of The FASEB Journal, published by the Federation of American Societies for Experimental Biology.

Guns kill, bombs kill and cigarettes kill," Dr. Gerald Weissmann, editor-in-chief of The FASEB Journal, said in a prepared statement. "While biologists can't do much about the first two, studies like this will help in the fight against tobacco-related death and disease. These experiments not only pinpoint new molecular targets for cancer treatment, but also identify culprits in cigarette smoke that eventually will do the smoker in."

Cigarette smoking, which causes more than 400,000 deaths a year in the United States (about one in five of all deaths) is the leading preventable cause of premature death in the country, according to the U.S. Centers for Disease Control and Prevention. Smoking causes 90 percent of all lung cancer deaths in men and about 80 percent of lung cancer deaths in women.

Tobacco smoke contains more than 4,000 chemical compounds, including 43 that are know to cause cancer, according to a U.S. Surgeon General report released in 2000.

More information

The U.S. National Cancer Institute has more about smoking and cancer.

-- Robert Preidt