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Cigarette smoke could be a cause of breast cancer after all, University of Florida researchers recently reported in a cellular cancer journal called Oncogene.
Breast cancer is one of the few cancers in which a link to smoking has never been clearly established, and researchers believe their findings could be important in helping to understand why more than 220,000 cases of the disease are diagnosed each year in the United States.
The Florida study differs in one key aspect from previous studies that have not found a clear link between smoking and breast cancer: The researchers used condensate from actual tobacco smoke, in which normal breast cells were exposed to the full range of the 4,000 chemicals in tobacco smoke and not just a few of its known toxins, and injected it into laboratory mice.
"It is very significant from a health point of view that in a single puff, you are taking in 4,000 chemicals, and we don't know what they are going to do, where they're going," said Dr. Satya Narayan, an associate professor of anatomy and cell biology at the University of Florida.
Toxins from cigarette smoke already have been implicated in more than 30 cancers, most notably lung cancer, the biggest cancer killer in the country. Smoking also has been linked to other major cancer killers, including cancer of the stomach, esophagus and colon. Many researchers over the years have tried, but failed, to determine whether a link exists between smoking and breast cancer, which claims 40,000 U.S. lives each year.
"It's actually been one of the cancers that has been shown not to increase with smoking," said Dr. Ruth O'Regan, director of Translational Breast Cancer Research at the Winship Cancer Institute at Emory University. Population studies that compare women with breast cancer to those who do not have the disease have not shown that women smokers are more likely to develop the disease, O'Regan said.
Still, O'Regan cautioned that the study may reveal more about the mechanism of how breast cancer starts rather than what is causing it.
Narayan's study was funded by the National Institutes of Health and the Flight Attendant Medical Research Institute, based in Miami.
Copyright 2006 The Atlanta Journal-Constitution
