PTGS2 and chronic rhinosinusitis: Reduced expression of COX-2 mRNA and/or proteins has been reported in nasal polyps and cultured fibroblasts from patients with AERD and non-AERD with respect to nasal mucosa controls or chronic rhinosinusitis without nasal polyps [15,16,18,19,20,21,23,24,25], with the lowest levels of COX-2 observed in nasal polyp samples and cultured fibroblast and epithelial cells from subjects with AERD [16,21,23,24,25].