Only recently, it was demonstrated that a pericryptal fibroblast subset expressing prostaglandin-endoperoxide synthase 2 (PTGS2, also known as cyclooxygenase-2 (COX-2)) could directly initiate the formation of adenomas in APC-mutant mice (fibroblast-specific targeting using COL6-driven Cre expression) [47]. Here, PTGS2 is linked to adenoma.