Our study confirmed that miR-21 increased in the nasal epithelium of CRSwNP compared with control subjects and that the expression of miR-21 was positively correlated with IL-10, and negatively correlated with IL-6, IL-8, IL-33, and TSLP in the epithelial cells of CRSwNP. This evidence concerns the gene IL33 and chronic rhinosinusitis with nasal polyps.