Invariant chain expression in gastric cancer

Invariant chain (Ii) is a chaperone molecule that inhibits the binding of e ndogenous antigens to HLA class II. The tumor cell with overexpressed Ii ch ain is thought to escape attacking cytotoxic lymphocytes by suppressing the host immune. However, the relationship between Ii expression by the tumor and clinicopathological factors in gastric cancer remains unclear. We studi ed 126 patients with gastric cancer who had undergone curative gastrectomy at Kagoshima University Hospital between 1988 and 1997. In order to detect Ii and HLA-DR expression by tumor cells, immunohistochemical staining with anti-CD74 and anti-HLA-DR antibodies were performed by avidin-biotin peroxi dase complex method. The 126 patients studied were divided into two groups based on Ii expression. Ii and HLA-DR were expressed both on the surface an d in the cytoplasm of tumor cells and tumor infiltrating lymphocytes. A tot al of 48 patients were identified as Ii positive, while the remaining 78 pa tients were Ii negative. Ii expression negatively correlated with the depth of invasion of the tumor as well as the patients' clinical stage. Ii expre ssion was negatively correlated with HLA-DR expression. Patients with Ii ne gative expression had significantly better surgical outcomes than those wit h Ii positive expression (P < 0.05). Ii expression in gastric cancer affect ed surgical outcome and Ii expression was negatively correlated with depth of invasion and HLA-DR expression. Ii expression in gastric cancer may be a prognostic factor related to suppressive effects on host immune responses to tumor cells. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.