Epithelial cell Cox-2 expression was driven from the endogenous Cox-2 gene rather than epithelial cell transgene expression based on the absence of consistent co-localization of lysozyme and Cox-2 proteins in epithelial cells (Fig. 4H–J) and our inability to detect transgenic transcripts in micro-dissected epithelium from transgenic adenomas (data not shown). This evidence concerns the gene PTGS2 and adenoma.