EXPRESSION OF HLA-ABC, HLA-DR AND INTERCELLULAR-ADHESION MOLECULE-1 IN ESOPHAGEAL-CARCINOMA

Aim-To examine the expression of HLA-ABC and HLA-DR major histocompati bility (MHC) antigens and intercellular adhesion molecule (ICAM)-1 in normal, inflamed, metaplastic, and neoplastic oesophageal tissue and i n freshly disaggregated tumours. Methods-Sequential sections of frozen tissue and cytospins of freshly disaggregated tumour were stained usi ng the ABC peroxidase system and monoclonal antibodies specific for HL A-ABC, HLA-DR and ICAM-1. Results-Normal oesophageal tissue showed pos itive staining for HLA-ABC in the basal layers of the oesophageal squa mous epithelium and on the epithelial cells of the submucosal oesophag eal glands. HLA-DR and ICAM-1 were not detected in either of these cel l types. In 20 of 37 (54%) carcinomas HLA-ABC was expressed weakly, wi th heterogeneous expression in nine (24%). Two tumours showed strong e xpression of HLA-ABC, but 15 of 37 (41%) were negative. HLA-DR and ICA M-1 were expressed weakly in six of 37 (16%) carcinomas without correl ation with each other or with the expression of HLA-ABC. Conclusions-H LA-ABC is absent from a high proportion of oesophageal carcinomas (41% ) and is otherwise variably and weakly expressed with strong expressio n in only a small fraction (3%). In other carcinomas there is a higher level of HLA-ABC expression. This discrepancy may partly explain the aggressive nature of oesophageal carcinomas. HLA-DR and ICAM-1 are not normally expressed on those cells from which oesophageal carcinomas a re thought to arise. The limited expression found here could suggest a partial or inhibited immune response against oesophageal carcinoma. I n vivo repressive factors may be involved.