MUC5B and head and neck cancer: Itcontributes to the formation of the thin salivary film on the oral mucosa, whichplays an important role in dry mouth perception.26 Patients treated with radiotherapy for head-and-neck cancer with highersalivary MUC5B levels suffer less from xerostomia than patients with low levels ofMUC5B in saliva.27 Similarly, in CD patients the disease-associated increase in salivary MUC5Bconcentration could counteract the expected increase in the severity ofxerostomia.