EXPRESSION OF CD44 VARIANT EXONS BY NORMAL ORAL EPITHELIA

Altered expression of CD44H and CD44 splice variants is associated wit h metastasis in several malignancies but its analysis requires knowled ge of the normal pattern. of expression which is tissue specific. Ther e are considerable regional variations in epithelial differentiation w ithin the mouth, including differences in cell surface glycoproteins. The aim of this study was to determine whether there are regional vari ations ire the expression of CD44 variants in oral epithelia. Frozen a nd formalin-fixed paraffin-embedded sections of lip vermilion border, buccal mucosa, dorsum and ventrum of tongue, floor Of mouth, gingiva a nd hard palate were stained immunohistochemically for CD44H and the pr oduct of variant exons v3, v4/5, v6 and v9. Parraffin sections were su bjected to microwave antigen retrieval. All epithelia stained strongly for all variants in basal, suprabasal and prickle cells and cornified and surface layers and the basal surface of basal cells were negative . Patterns of staining were identical in frozen and formalin-fixed tis sue. Despite the structural heterogeneity within oral epithelium, no r egional variation was detected. (C) 1997 Elsevier Science Ltd.