Issues

The cover image is a photomicrograph of an A/J mouse's lung section stained with hematoxylin and eosin (courtesy of M. Christine Hollander and Phillip A. Dennis). The mouse was treated with intraperitoneal injections of the tobacco carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK; 3 weekly doses of 100 mg/kg starting at 6 weeks of age), and lungs were harvested 16 weeks after treatment started. Histologically normal alveoli (honeycomb-like structures) are present throughout the section, and the large, empty spaces bordered by purple-stained bronchial epithelium are normal bronchioles. A lung tumor (purple mass) is evident at the lower right. In vitro studies have suggested that nicotine (whose chemical structure is superimposed on the lung section) enhances cancer cell growth, but mousemodel studies suggest otherwise, as reported in this issue of the journal. This issue is of critical importance as the FDA considers approval of long-term nicotine replacement therapy for smoking cessation. See articles by Maier et al. (beginning on page 1743), Murphy et al. (beginning on page 1752), Lam and Minna (beginning on page 1724), and Shields (beginning on page 1719) for more information.