MUC5AC and lung disorder: Interestingly, the MUC5AC mucin is increased in amounts at lung diseases (Fahy and Dickey, 2010; Fernandez-Blanco et al, 2018) where the surface goblet cells co-express both MUC5B and MUC5AC in the same cell (Hoang et al, 2022), leading to the formation of an attached stratified mucus layer (Fernandez-Blanco et al, 2018).