By Janet Raloff
Nonsmokers living with a smoker have an elevated risk of lung cancer. In efforts to pinpoint the reason, researchers have now found evidence of a potent tobacco-specific carcinogen in nonsmokers exposed to smoke at home.
In the past, researchers have linked cigarette smoke to lung cancer in nonsmokers by finding noncarcinogenic cigarette compounds, including nicotine, in nonsmokers’ blood or urine. These compounds confirmed home exposure to smoke, but not necessarily to smoke’s carcinogens.
So, Kristin E. Anderson and her colleagues at the University of Minnesota’s Comprehensive Cancer Center in Minneapolis focused on a nitrosamine known as NNK, which scientists believe plays a major role in smoking-induced lung cancers. Not only do smokers possess high concentrations of NNK in their bodies, but animals treated with this compound develop the lung tumor that typifies smoking-related cancer in people.