In human IBD including both ulcerative colitis and Crohn’s disease, mPGES-1 was also found to be expressed in the epithelial and inflammatory cells that surround the damaged crypt in the colon during active colitis [28]; this result strongly supports our finding of colonic localization of mPGES-1, which we propose to be responsible for elevated colonic PGE2 production during colitis. This evidence concerns the gene PTGES and ulcerative colitis.