Campus Connection

Waiting to exhale
(continued)

In 1992 the federal Environmental Protection Agency, using epidemiological studies, declared secondhand smoke to be a human carcinogen. Nevertheless, questions remain: At what concentrations does secondhand smoke cause cancer? Over what period of time? And more importantly, can drugs or diet make a difference in preventing cancer?

In research published in the May issue of the journal Carcinogenesis, Witschi answers this latter question in the affirmative. His lab found a diet of dexamethasone, a corticosteroid used to treat asthma, and myoinositol, a substance found in cereal bran, to be effective in preventing lung cancer in male mice exposed to heavy tobacco smoke. It is, Witschi believes, the first animal model study to test substances that might prevent smoking-induced lung cancer.

"We tested several compounds that had previously been shown to prevent cancer, but these studies were done on mice injected with tobacco carcinogens," says Witschi. "These agents didn't work in mice who had inhaled smoke, a model that has much more in common with how humans develop lung cancer."

Witschi, himself a reformed smoker, has spent 20 years tracking acute pulmonary disease. A medical doctor and professor of toxicology, he studies adenocarcinoma of the lung, the most common tumor found in smokers.