While colitis pathogenesis studies have mainly focused on immune cells and microbiota, our recent studies have shown that stromal cell-generated PGE2 plays a critical role in suppressing colitis development and IBD patients show a reverse correlation between the levels of Cox2 (an enzyme to synthesize PGE2) expression in colorectal stromal cells and severity of the disease [73]. Here, PTGS2 is linked to inflammatory bowel disease.