Immunohistochemical study on S100 protein-positive dendritic cells in patients with gastric carcinoma

Abstract

The density of dendritic cells (DC) and macrophages (Mϕ) in tissue specimens of gastric carcinoma (GC n=65) was investigated by ABC immunohistochemical method using anti-S100 protein and anti-lysozyme antibodies, and was compared with that in gastric ulcer (GU n=19), chronic atrophic gastritis (CAG n=28) and normal gastric mucosa (NGM n=15). The mean density if DC (cells/mm²) in GC (15.0 was significantly higher than that in NGM (3.8) and GU (8.3), but was remarkably lower when compared to that in CAG (29.5) (P<0.01). Statistically significant difference in the population density of DC was observed between well- and poorly-differentiated GC (P<0.01). With their unique dendritic processes, DC were mainly concentrated within dense lymphoid infiltrates or in the T-area of reactive lymphoid follicles and were interspersed among the tumor cells. In contrast, Mϕ were present around the necrotic foci and were rarely seen within the non-necrotic neoplastic tissues. These data suggest that DC, which differ in morphology, distribution, number and function form Mϕ may be more directly involved in the host immune reaction against tumor by acting as antigen presenting cells.