The trial development group (including clinical researchers, statisticians, trialists, and patient representatives) chose to assess the selective COX-2 inhibitor, celecoxib, because data suggest that it is better tolerated than other NSAIDs, exhibits activity as a cancer-preventing agent,18 and shows inhibition of angiogenesis and induction of apoptosis in human cancer cells including prostate cancer,19 particularly at higher doses.20 This evidence concerns the gene PTGS2 and cancer.