INTERCELLULAR-ADHESION MOLECULE-1 EXPRESSION BY MACROPHAGES IN HUMAN GASTROINTESTINAL CARCINOMA - POSSIBLE ROLES AS HOST IMMUNE INFLAMMATORY REACTION

Tumor-associated macrophages (TAM) are one of the factors which modula te the carcinoma progression, The present study described immunohistoc hemical expression of intercellular adhesion molecule-1 (ICAM-1) in st romal cells in human gastrointestinal carcinoma identifying the cell t ypes by immunoelectron microscopy, In colon and gastric carcinomas, IC AM-1-positive cells were mostly stromal cells, and major cell types we re identified as macrophages and fibroblasts by immunoelectron microsc opy. Macrophages were characterized by their ovoid shape, cytoplasmic projections, abundant vacuoles, phagocytosis, and paucity of rough end oplasmic reticulum. Fibroblasts contained stacks of rough endoplasmic reticulum. Macrophages were major cells among ICAM-1-positive cells al ong the invasive margin, while fibroblasts were predominant in the str oma within carcinoma in colon and intestinal-type gastric carcinomas, Lymphocytes positive for lymphocyte function associated antigen (LFA-1 ), a counter-receptor of ICAM-1, were densely distributed along the in vasive margin, and sparsely in the stroma within carcinoma. In diffuse -type gastric carcinoma, most macrophages were dendritic-shaped and ne gative for ICAM-1. Our study suggests that the invasive margin is an a rea similar to active inflammation, where the antigen presenting cells (macrophages) and lymphocytes may interact via the ICAM-1/LFA-1 adhes ion.