In conclusion, this study has shown that treatment with the growth factor EGF upregulates the expression of MUC5AC in HNECs from CRSwNP via a pathway, which is likely to involve PI3K-TMEM16A signalling, and provides novel insights into the molecular mechanism of mucus hypersecretion in nasal polyps. The gene discussed is MUC5AC; the disease is chronic rhinosinusitis with nasal polyps.