In total, 24 nasal tissue samples of control, CRSsNP, and CRSwNP patients were measured, it was found that the COX-2 mRNA level in the NP tissues of CRSwNP was significantly higher than that expressed in the control nasal mucosa tissues, as quantified by the densitometric analysis (Fig. 1a). Here, PTGS2 is linked to chronic rhinosinusitis without nasal polyps.