CD44 EXPRESSION IN DYSPLASTIC EPITHELIUM AND SQUAMOUS-CELL CARCINOMA OF THE ESOPHAGUS

The molecular events involved in the development of esophageal dysplas ia and carcinoma are poorly understood. We examined the expression of CD44, a cell-adhesion molecule, in normal and dysplastic epithelia and in squamous-cell carcinoma (SCC) of the esophagus. A monoclonal antib ody (MAb) which recognized all CD44 isoforms and 2 MAbs specific to th e CD44v3 and CD44v6 splice variants were used to detect CD44 isoforms in 50 archival specimens. A semi-quantitative scoring system based on the extent and intensity of the immunostaining was used to quantify CD 44 expression. In normal epithelium, expression of CD44 was strongest in the basal-cell layer and weak or absent in surface cells. Expressio n of CD44 was increased in dysplastic epithelium as compared with norm al epithelium. The extent of this increase correlated directly with th e severity of dysplasia. CD44 was expressed in all SCCs, but the exten t and intensity of immunostaining varied with areas of tumor different iation. The well-differentiated components showed greater CD44 express ion than the moderately and poorly differentiated components. The patt erns of expression of CD44v3 and CD44v6 were strikingly similar to tha t of total CD44 in normal, dysplastic and malignant esophageal epithel ia. Thus, changes in expression of these splice variants likely accoun t to some extent for the changes in total CD44 expression observed in the dysplastic and malignant transformation of the esophagus. Our resu lts suggest that changes in the expression of CD44 may be involved in the development of esophageal dysplasia as well as SCC. (C) 1996 Wiley -Liss, Inc.