In the control group, a noted amount of COX-2 expression was observed mainly in subcutaneous glands (gland; g) and partially in the epithelium (epithelium; epi) and vessels (denoted as v); however, of the patients with CRSwNP examined, the COX-2 was markedly increased in the epidermal cell layer and submucosal stroma area. This evidence concerns the gene PTGS2 and chronic rhinosinusitis with nasal polyps.