Distribution of MUC1 in the normal human oral cavity is localized to the ducts of minor salivary glands

The change in expression of MUC1 from health to disease forms the basis of its use as a potential disease marker. Previous attempts at isolating MUC1 from normal, healthy human oral mucosa have, however, drawn conflicting con clusions as to its presence. Furthermore, when MUC1 was detected in the ora l glycocalyx, it was not clear which cells were synthesising it. We examine d human oral glycocalyx using pooled buccal smears from 50 normal individua ls. Following isopycnic density centrifugation and membrane extraction with octyl glucoside and saponin, MUC1 was detected with the polyclonal antibod y CT1. Immunohistochemistry using antibodies CT1 and BC2 was performed on s ections from eight labial, seven palatal, four buccal, three retromolar pad , three dorsum of tongue and two ventral surface of tongue biopsies. In-sit u hybridisation using MUC1 and cytoplasmic tail oligoprobes on sections fro m four palatal, seven labial and two retromolar pad biopsies was also carri ed out. MUC1 mRNA could only be detected in the minor salivary mucous gland s. MUC1 has already been identified in the ducts of normal parotid and subm andibular gland, and our findings demonstrate a similar distribution in min or salivary glands. We conclude that when present in the normal oral glycoc alyx, the only oral source of MUC1 is from cell membranes of the minor sali vary glands. (C) 2001 Elsevier Science Ltd. All rights reserved.