Scott Hickman is global market segment manager for toxicology, BioReliance (part of Sigma-Aldrich), 14920 Broschart Rd., Rockville, Md. 20850-3349, U.S.A.; tel.: 301-738-1000; fax: 301-610-2590; e-mail: [email protected]; www.bioreliance.com. BioReliance has more than 15 years of experience working with transgenic models for carcino- genicity assessment. Through the National Toxicology Program, the company was involved in the