To date, some investigators have proposed that periostin is produced locally in the sinonasal tissues and might contribute to polyp formation16, 17; meanwhile, we had found that patients with ENP were more likely to be atopic18, so we speculate that periostin might play an important role in tissue remodeling in NP via inducing VEGF, RANTES and eotaxin-2 production. The gene discussed is POSTN; the disease is polyp.