Higher Risk of Lung Cancer Among Blacks Explained

Robert Preidt:

High rates of lung cancer in black Americans may be the result of faulty cell cycle "checkpoints" that don't respond effectively to DNA damage, according to a report in the Oct. 15 issue of Cancer Research.

This study, by researchers at Georgetown University and the U.S. National Cancer Institute, is the first epidemiological study to identify an association between the efficiency of the G2/M checkpoint and lung cancer risk in black Americans.

The investigation, which included 216 lung cancer patients and 340 cancer-free people, found that the G2/M checkpoint was less effective in black lung cancer patients. This association was especially strong in black women. Those with a faulty G2/M checkpoint had nearly five times the risk of lung cancer compared to women with an efficient G2/M checkpoint.

The researchers did not find any association between this checkpoint and lung cancer risk in whites.

"Although the study has limitations, our findings suggest one possible explanation for the higher incidence of lung cancer in African-Americans, who as a group smoke less than whites, yet still develop more lung cancer at comparatively younger ages," study author Dr. Yun-Ling Zheng, an assistant professor in the department of oncology at the Lombardi Comprehensive Cancer Center at Georgetown University, said in a prepared statement.

The incidence of lung cancer in black American men was 42 percent higher than in white men, and the risk of lung cancer for black women was 13 percent higher, said a 2002 report by the Surveillance, Epidemiology and End Results (SEER) program.

"Epidemiologists have long known that cancers are expressed at varying rates in different racial groups, but we are only now able to use advanced research techniques to look at the molecular reasons for these disparities. The value of such research is that it can provide new tools for risk calculation," Zheng said.

More evidence that racial differences are biological, not sociological.