Background: The purpose of this study was to investigate the local immune response to tumor invasion in esophageal squamous cell carcinoma by using an immunohistochemical examination of the expression of human leukocyte antigen- (HLA) DR and lymphocyte infiltration.
Methods: The paraffin embedded sections from 108 patients with esophageal squamous cell carcinoma were studied immunohistochemically, using the streptavidin biotin peroxidase method with monoclonal antibody (HLA-DR, T-cell, and B-cell) in the 68 noninvasive sites of cancer (intraepithelial carcinoma) and the 108 invasive sites of cancer.
Results: The expression of HLA-DR antigen was detected in 49 of 108 cases (45%) of esophageal cancer. The expression of this antigen was more predominant in intraepithelial carcinoma than at the invasive sites of cancer (60% versus 22%, P < 0.01). Among the 40 cases with positive staining for HLA-DR antigen in intraepithelial carcinoma, negative staining of the invasion portion was shown in 27 (67.5%) cases. On the other hand, in the 28 cases with negative staining in intraepithelial carcinoma, 27 cases (96.4%) were also negative at the invasive sites. T-cell infiltration was significantly recognized at the area of HLA-DR antigen expression at the sites of both intraepithelial carcinoma and tumor invasion. However, no significant relationship was observed between the HLA-DR antigen expression and long term survival at this time.
Conclusions: These results suggest that the local immune response to the HLA-DR may prevent tumor invasion, whereas the negative expression of HLA-DR antigen is a significant factor facilitating tumor invasion in esophageal squamous cell carcinoma.