HLA-DR antigen expression in squamous epithelial dysplasia and squamous cell carcinoma of the esophagus: An immunohistochemical study

To clarify the biologic significance of esophageal squamous epithelial dysp lasia, especially the similarity to carcinoma in situ, immunohistochemical investigation of HLA-DR antigen expression and lymphocyte infiltration was performed. HLA-DR antigen was expressed in 12 of the 35 invasive carcinomas (34.4%), 23 of the 38 intraepithelial carcinomas (60.5%), 21 of the 50 are as of dysplasia (42.0%) and only 2 of the 625 specimens of non-cancerous sq uamous epithelium (0.3%). The HLA-DR-positive rate of dysplasia localized c ontinuous to HLA-DR-positive carcinoma was 68.4%, which was significantly h igher than that for HLA-DR positive dysplasia localized continuous to HLA-D R negative cancer (11.1%) (p<0.05). In areas of dysplasia and intraepitheli al carcinoma, T cell infiltration was significantly increased at the sites of HLA-DR antigen expression (P<0.01). B cell infiltration was also more co mmon in areas of positive expression. These results suggest that HLA-DR ant igen is associated with the local immune response to squamous epithelial dy splasia, and that HLA-DR antigen expression may prevent tumor invasion simi larly to its role in intraepithelial carcinoma.