Evidence from animal studies suggests that aspirin and possibly other nonsteroidal anti-inflammatory drugs (NSAIDs) including cyclooxygenase-2 (COX-2) inhibitors may influence the development and progression of lung cancer (Duperron and Castonguay, 1997; Rioux and Castonguay, 1998; Yao et al, 2000). This evidence concerns the gene PTGS2 and lung cancer.