POSTN and chronic rhinosinusitis without nasal polyps: To investigate this, we measured the concentrations of MMPs, TIMPs, periostin and tenascin C in tissue homogenates of patients with CRSsNP, CRSwNP and control subjects and analyzed their relationships; and stimulated ex vivo cultured nasal polyp‐derived primary human fibroblasts and epithelial cells with periostin and tenascin C to detect the gene expression of MMPs and TIMPs.