PTGS2 and chronic rhinosinusitis with nasal polyps: 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).